# NVIDIA PCI-Express Resizable BAR Performance Test



## W1zzard (Apr 2, 2021)

PCI-Express Resizable BAR, pioneered by AMD, seems to be a magic bullet for unlocking additional double-digit FPS gains. NVIDIA finally released their implementation for GeForce Ampere cards. In our PCIe BAR review, we test the feature on RTX 3090, 3080, 3070, and 3060 Ti in 22 games, at Full HD, 1440p, and 4K.

*Show full review*


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## Ravenlord (Apr 2, 2021)

Good addition for non-existing hardware. Many minor features makes difference in performance at all, so keep adding more..


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## TheoneandonlyMrK (Apr 2, 2021)

Not bad seems a bit pointless to care about ATM though.
One thing though, at the end you say AMD were lucky, it's not luck if you plan an introduction of a new technology and implement it well, before the competition, luck isn't involved.
Still,
Wouldn't make me buy, or not , even if I could that is, the gains are minimal.


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## Xuper (Apr 2, 2021)

> AMD wants to sell you the overpriced Ryzen 9 5900X.The 5800X is actually the faster processor for gaming,due to its CCD design, and much more affordable, too.



lol


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## Camm (Apr 2, 2021)

Umm, did I miss somewhere in the article that you got around the profile limitation for Resizeable Bar?

https://www.nvidia.com/en-us/geforc...&ranSiteID=TnL5HPStwNw-M0kzgbvCZtWOGggallYRLw

“Game Ready Driver Update
In practice, the performance benefits of Resizable BAR can vary substantially from game to game. In our testing, we’ve found some titles benefit from a few percent, up to 12%. However, there are also titles that see a decrease in performance, so NVIDIA will be pre-testing titles and using game profiles to enable Resizable BAR only when it has a positive performance impact. That way you won’t have to worry about bugs or performance decreases, and won’t have to rely on the community to benchmark each title and discover whether Resizable BAR is beneficial in the games you’re playing.”


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## xkm1948 (Apr 2, 2021)

Yeah free new features. Too bad my X99 wont be able to enjoy that


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## AsRock (Apr 2, 2021)

TheoneandonlyMrK said:


> Not bad seems a bit pointless to care about ATM though.
> One thing though, at the end you say AMD were lucky, it's not luck if you plan an introduction of a new technology and implement it well, before the competition, luck isn't involved.
> Still,
> Wouldn't make me buy, or not , even if I could that is, the gains are minimal.



Maybe when games are designed to use it we might see better performance ?, but like every thing else it's going to take time.

As you said time will tell, Going be like the CPU threads used to be.


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## W1zzard (Apr 2, 2021)

Camm said:


> Umm, did I miss somewhere in the article that you got around the profile limitation for Resizeable Bar?


No? I just tested all my games


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## Mats (Apr 2, 2021)

Resizable BAR, such confusing words. Just as logical as Double DR, Random AM, Basic IOS, Advanced MRAAM, Situation NAFU, Senatus PQR..

"No, we can't abbreviate _Resizable_, but everyone knows what _BAR_ means"

*Before you shoot me down*, I know, the BAR in this context is older than Resizable BAR.
How about just R-BAR?


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## Ja.KooLit (Apr 2, 2021)

Mats said:


> Resizable BAR, such confusing words. Just as logical as Double DR, Random AM, Basic IOS, Advanced MRAAM, Situation NAFU, Senatus PQR..
> 
> "No, we can't abbreviate _Resizable_, but everyone knows what _BAR_ means"
> 
> ...


Wizz actually put SAM in his conclusion. (2nd sentence last paragraph)


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## RH92 (Apr 2, 2021)

Thanks for the nice review W1zzard .  At the end of the day 2-4% on average is not a game changer but obviously it's always good to take especialy given it comes for free . I believe there is not much else to say other than this .


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## Mats (Apr 2, 2021)

night.fox said:


> Wizz actually put SAM in his conclusion. (2nd sentence last paragraph)


Sorry, I meant just in general. You can see "Resizable BAR" everywhere, and after a while it gets silly, just like my made up examples.


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## W1zzard (Apr 2, 2021)

Mats said:


> How about just R-BAR?


Not a lot of Google results for it, slightly more for ReBAR, not enough to make me switch



night.fox said:


> Wizz actually put SAM in his conclusion. (2nd sentence last paragraph)


Whoops, lol, fixed


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## Ravenmaster (Apr 2, 2021)

Wel that went down like a led balloon. 1 FPS difference with RE BAR on... pfff


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## efikkan (Apr 2, 2021)

Camm said:


> “…there are also titles that see a decrease in performance, so NVIDIA will be pre-testing titles and using game profiles to enable Resizable BAR only when it has a positive performance impact. That way you won’t have to worry about bugs or performance decreases, and won’t have to rely on the community to benchmark each title and discover whether Resizable BAR is beneficial in the games you’re playing.”


I don't mind a little bit of free performance, even if it's just a little bit.
But what worries me is what kind of complexity they added to achieve this.
Even more so, if that quote is accurate, they should rather have made it an API call to enable it, instead of some whitelisting. That phrasing there makes me as a programmer worried about the reliability of this feature.


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## TheLostSwede (Apr 2, 2021)

W1zzard said:


> Not a lot of Google results for it, slightly more for ReBAR, not enough to make me switch


ReBAR seems top bring up a lot of results...


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## mechtech (Apr 2, 2021)

TheLostSwede said:


> ReBAR seems top bring up a lot of results...


mmmmmmmmmmm  love me some reinforcing bar................well the civil guys like it in their concrete anyway


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## BigMack70 (Apr 2, 2021)

Good stuff. Free performance is always a win. I didn't have any trouble updating my z390 / 3080 founders setup to use the new feature even though Nvidia's site didn't specify z390 as compatible.


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## nguyen (Apr 2, 2021)

noice, 4K is the resolution that need every single FPS and seems like Resizeable Bar works best at 4K too.
If Nvidia had include the option to toggle Resizeable Bar On/Off per game profile then this would be a superior approach AMD one, where you need to go to BIOS to disable SAM just so you don't get performance regression in certain game.


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## Transient Gamer (Apr 2, 2021)

Very nice Wizzard, as always. I flashed my Asus 3070 TUF OC with my eyes closed, not kidding and hey it worked! GPU-Z is a quick and easy way to confirm too! I really appreciate your coverage in those BAR supported titles. Is the 99% and/or 99.9% lows have improved to the same percentage as the FPS?
I mean that difference in FPS is telling, but do you believe it is the same story proportionally on the frametime analysis front? Maybe the story is even better or the same?
Your thoughts?


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## Redkaliber (Apr 2, 2021)

Thanks Nvidia, I'm sure the miners will make great use of these new features!


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## Metroid (Apr 2, 2021)

I dont think 2% will make people wanting it that badly, if it was 10% then it would be a different story. Thanks for the tests @wizard.


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## R00kie (Apr 2, 2021)

Transient Gamer said:


> Is the 99% and/or 99.9% lows have improved to the same percentage as the FPS?


This.

AVG fps is good and all, but it isn't the full picture.


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## Deleted member 205776 (Apr 2, 2021)

Honestly, after enabling ReBar on my system, my games feel noticeably smoother. And it's not placebo.


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## Chane (Apr 2, 2021)

Enabling ReBAR on my system brought out some instability I didn't know I had when playing Cyberpunk. I guess thanks ReBAR for helping me realize my infinity fabric overclock wasn't stable. Now that everything is working it does feel a little bit better to play, but that could also be the Cyberpunk 1.2 patch that came out. Oh well, happy to get any little bit of performance I can.


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## chrcoluk (Apr 2, 2021)

Similar to my own testing, I have been testing mainly dx9/dx11 stuff since all the reviewers mostly focus on dx12.

I also tested 3dmark timespy.

My conclusion is the majority of stuff gets 0-2% benefit.

Also I have discovered having REBAR enabled on the system, even if its disabled in the game, there is a very small overhead, its small maybe about 0.5 to 1%. Usually the REBAR gain (if enabled in inspector) will cancel it out. So the net gain over a system with REBAR disabled is actually closer to 0-0.5%.

I will speculate since this feature was planned by AMD, they likely contacted some game dev's had some optimisation done and hence we have a bunch of new titles with decent gains (that can showcased by reviewers) whilst most other titles is barely anything at all. In that respect its kind of like DLSS, benefits newer stuff but not older stuff.


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## efikkan (Apr 2, 2021)

chrcoluk said:


> Also I have discovered having REBAR enabled on the system, even if its disabled in the game, there is a very small overhead, its small maybe about 0.5 to 1%. Usually the REBAR gain (if enabled in inspector) will cancel it out. So the net gain over a system with REBAR disabled is actually closer to 0-0.5%.
> 
> I will speculate since this feature was planned by AMD, they likely contacted some game dev's had some optimisation done and hence we have a bunch of new titles with decent gains (that can showcased by reviewers) whilst most other titles is barely anything at all. In that respect its kind of like DLSS, benefits newer stuff but not older stuff.


Anything this low level isn't controlled directly by the game engines, this is all done by the graphics drivers.

I am worried though, if any of them (AMD or Nvidia) added workarounds in their drivers for specific games. Such "optimizations" are never a good idea, they add complexity to drivers, potential bugs, and generally adds to driver overhead.


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## voltage (Apr 2, 2021)

"but most motherboard vendors for whatever reason restricted their Resizable BAR enabling BIOS updates to the 300-series chipset, or 8th Gen "Coffee Lake" (and later)" 

maybe these motherboard vendors bought amd shares at the time. after all, that seems like intentional performance restriction, why else would they choose to restrict Intel's performance?


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## toilet pepper (Apr 2, 2021)

Chane said:


> Enabling ReBAR on my system brought out some instability I didn't know I had when playing Cyberpunk. I guess thanks ReBAR for helping me realize my infinity fabric overclock wasn't stable. Now that everything is working it does feel a little bit better to play, but that could also be the Cyberpunk 1.2 patch that came out. Oh well, happy to get any little bit of performance I can.


I've been seeing posts in reddit about this. Basically, if you have your OC pushed to the limit and stable and you enable ReBar - you have to dial your OC a notch to make it stable.


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## cellar door (Apr 2, 2021)

Chane said:


> Enabling ReBAR on my system brought out some instability I didn't know I had when playing Cyberpunk. I guess thanks ReBAR for helping me realize my infinity fabric overclock wasn't stable. Now that everything is working it does feel a little bit better to play, but that could also be the Cyberpunk 1.2 patch that came out. Oh well, happy to get any little bit of performance I can.


Same exact experience here as well - I went from 1900 to 1866mhz to correct it.


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## so11ex (Apr 2, 2021)

Great review, thanks!


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## lightning70 (Apr 2, 2021)

Every performance increase from free is good. But it has increased a little.


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## Fierce Guppy (Apr 3, 2021)

Well, it was interesting to learn that even the Haswell CPU supports ReBAR in hardware.   So it's a matter of firmware and microcode support limiting the availability of ReBAR.


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## Xenom (Apr 3, 2021)

A tech that will be useable to the general person in 2-5 years when the cards are available


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## qubit (Apr 3, 2021)

Wow, makes a real difference at 1080p, not so much at 4K where hard performance limitations of the graphics card, like fill rate, have a bigger effect. Worth having if you can get it, though. My next rig will be built with this in mind. Should be standard by then, anyway.

Great review W1z, as always.


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## Yopis (Apr 3, 2021)

This test was a fail. at least for Red Dead if you actually play the game then you'll see that the performance increases a lot larger this is one of the things that people have figured out that reviewers that didn't take any time except running The in-game benchmark didn't realize try it again actually playing the game in the same spot and you'll see market improvement and 1% lows and regular frame rate I'm seeing five to six frame increase a lot larger than the in-game benchmark shows me don't be lazy and actually try the game as well. I'm referring to 4k.












Metroid said:


> I dont think 2% will make people wanting it that badly, if it was 10% then it would be a different story. Thanks for the tests @wizard.


The test were flawed.


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## R0H1T (Apr 3, 2021)

chrcoluk said:


> I will speculate since this feature was planned by AMD


Or maybe it has something to do with that software scheduler thing & actually better planning from AMD in the past?











voltage said:


> why else would they choose to restrict Intel's performance?


You're kidding right? You remember the last BIOS updates for Haswell/Broadwell gen boards? No(?) ~ it was for smeltdown & probably only because Intel forced them to! You think board makers will update BIOSes for boards released 5-7 years back? It's not like they can be used for CPUs released even 2 years back, unlike AMD & AM4. You're *almost funny*, if not for the pathetic thing Intel does forcing users to update mobos nearly each year!


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## Night (Apr 3, 2021)

If this was supposed to be marketing for the GPU, why even release it now? By the time GPUs get available again, no one will remember Resizable BAR. Especially with such small improvements on select titles, it's important as much as Raytracing is.


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## W1zzard (Apr 3, 2021)

Yopis said:


> The in-game benchmark


I'm not using the integrated benchmark


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## stimpy88 (Apr 3, 2021)

Thanks w1zzard.


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## TheoneandonlyMrK (Apr 3, 2021)

Night said:


> If this was supposed to be marketing for the GPU, why even release it now? By the time GPUs get available again, no one will remember Resizable BAR. Especially with such small improvements on select titles, it's important as much as Raytracing is.


I get your point, but definitely disagree on how important it is, Raytracing is over hyped at the moment(IMHO) and this isn't anywhere near as important to performance or the end game Feel or look.


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## Ravenas (Apr 3, 2021)

MSI hasn't offered a BIOS update to their X570 MSI ACE MEG board yet. Only for SAM.


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## Sora (Apr 3, 2021)

> You can use NVIDIA Profile Inspector to modify Resizable BAR game support settings. Credit goes to @chrcoluk.




 yeah because i didn't already post this info to TPU 4 weeks ago or anything.



R0H1T said:


> Or maybe it has something to do with that software scheduler thing & actually better planning from AMD in the past?



Oh, ffs, please don't cite anyone about the bloody scheduler, the only thing nvidia removed was the data hazard block leaving instruction dispatch up th the compiler, the rest of the bloody scheduler is still hardware based.

I would love to punch Ian in the face for misrepresenting what he was told in the kepler review all those years ago.



Chane said:


> Enabling ReBAR on my system brought out some instability I didn't know I had when playing Cyberpunk. I guess thanks ReBAR for helping me realize my infinity fabric overclock wasn't stable. Now that everything is working it does feel a little bit better to play, but that could also be the Cyberpunk 1.2 patch that came out. Oh well, happy to get any little bit of performance I can.



If you find any games get stuttery, you can thank Ryzens poor grading of IO dies and the numerous cpu's that spam the pcie controller with errors.


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## blu3dragon (Apr 4, 2021)

Anyone seeing





chrcoluk said:


> Similar to my own testing, I have been testing mainly dx9/dx11 stuff since all the reviewers mostly focus on dx12.
> 
> I also tested 3dmark timespy.
> 
> ...


Did you see an improvement in timespy?

I tried it today, and the GPU portion was basically within margin of error, but my cpu score dropped a bit when I used profile inspector to enable it.

The one game I tried forcing it on for showed zero difference.  It's an older dx11 architecture and doesn't use a huge amount of memory.


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## nguyen (Apr 4, 2021)

blu3dragon said:


> Anyone seeing
> Did you see an improvement in timespy?
> 
> I tried it today, and the GPU portion was basically within margin of error, but my cpu score dropped a bit when I used profile inspector to enable it.
> ...



Try console ported games, the idea behind Resizeable Bar or SAM is because console CPU have direct access to VRAM after all.
Games that are made on PC originally are unlikely to gain much from Re-Bar or SAM


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## Sora (Apr 4, 2021)

nguyen said:


> Try console ported games, the idea behind Resizeable Bar or SAM is because console CPU have direct access to VRAM after all.



no it isn't.


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## Metroid (Apr 4, 2021)

Ravenas said:


> MSI hasn't offered a BIOS update to their X570 MSI ACE MEG board yet. Only for SAM.



I have that msi b450 gaming plus and I can confirm it got a bios for it and in the bios there is an option to enable rebar, however I have not done the test yet to confirm if it works with the 3xxx series, i have a 3080 but not using as main gpu right now, I'm using a gtx 1070 as main and rebar does not work with pascal yet, yeah only 3xxx series but like i said i have to confirm it.


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## chrcoluk (Apr 4, 2021)

blu3dragon said:


> Anyone seeing
> Did you see an improvement in timespy?
> 
> I tried it today, and the GPU portion was basically within margin of error, but my cpu score dropped a bit when I used profile inspector to enable it.
> ...


yes but its tiny, basically it cancelled out the bios overheads.


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## Prima.Vera (Apr 5, 2021)

Wait, except for the driver, you also have to re-flash your GPU, not only your Mobo????


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## W1zzard (Apr 5, 2021)

Prima.Vera said:


> Wait, except for the driver, you also have to re-flash your GPU, not only your Mobo????


Correct, and you might have to reinstall Windows or MBR2GPT


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## cazzie.nl (Apr 5, 2021)

Hello TPU, i am wondering something ... Those whom have the correct specs for BAR can see a 'large memory range' in device mamager / display adapter.
I found this pic elsewhere here on tpu so it is not a screenshot of mine hardware specs, it is just an example.

1: regedit: can we fiddle around to make windows believe we have compatible hardware to make Resizable BAR work ?

2: do we have to wait for custom made firmware / vbios for non-supported hardware ?

What are your thoughts


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## Sora (Apr 5, 2021)

cazzie.nl said:


> 1: regedit: can we fiddle around to make windows believe we have compatible hardware to make Resizable BAR work ?



no.


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## Lycanwolfen (Apr 5, 2021)

It's funny I look at those numbers in 4k and my SLI setup spanks everyone of them.


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## Franzen4Real (Apr 5, 2021)

Thank you for the great article @W1zzard. Do you happen to have a write up here on the site that would help to better understand Frame Distribution and Frame Time, and how those graphs correlate to what we experience in game?



Alexa said:


> Honestly, after enabling ReBar on my system, my games feel noticeably smoother. And it's not placebo.


Just curious if you're also running freesync or gsync with rebar enabled?


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## Deleted member 205776 (Apr 5, 2021)

Franzen4Real said:


> Just curious if you're also running freesync or gsync with rebar enabled?


My monitor is G-Sync but I don't use it as games that are locked to 60 FPS stutter.


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## W1zzard (Apr 5, 2021)

cazzie.nl said:


> Hello TPU, i am wondering something ... Those whom have the correct specs for BAR can see a 'large memory range' in device mamager / display adapter.
> I found this pic elsewhere here on tpu so it is not a screenshot of mine hardware specs, it is just an example.
> 
> 1: regedit: can we fiddle around to make windows believe we have compatible hardware to make Resizable BAR work ?
> ...


1) no, the resource allocations are created by the driver on startup
2) i doubt that modders can build an unofficial firmware with bar support


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## R-T-B (Apr 6, 2021)

W1zzard said:


> 2) i doubt that modders can build an unofficial firmware with bar support


Even if they could, nvidia signs firmware blobs now, so autonope.


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## W1zzard (Apr 6, 2021)

R-T-B said:


> Even if they could, nvidia signs firmware blobs now, so autonope.


That too


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## Ravenas (Apr 6, 2021)

Metroid said:


> I have that msi b450 gaming plus and I can confirm it got a bios for it and in the bios there is an option to enable rebar, however I have not done the test yet to confirm if it works with the 3xxx series, i have a 3080 but not using as main gpu right now, I'm using a gtx 1070 as main and rebar does not work with pascal yet, yeah only 3xxx series but like i said i have to confirm it.



I have the option for rebar, but it restricted to SAM technology only.


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## Viruzz (Apr 9, 2021)

Redkaliber said:


> Thanks Nvidia, I'm sure the miners will make great use of these new features!


Not just miners.


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## watzupken (Apr 16, 2021)

I think it will be good to see AMD with SAM enabled vs Nvidia with ReBar enabled in the charts.


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## KLMR (Apr 21, 2021)

The use of updated BIOS and drivers makes me wonder if you have noticed any drop in FP32 or INT8/16 performance since the update.
nVIDIA wants to sell their crypto-p-oos and maybe they have introduced limiters in those fields in drivers, bios or both.

Any news on that?


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## W1zzard (Apr 21, 2021)

KLMR said:


> The use of updated BIOS and drivers makes me wonder if you have noticed any drop in FP32 or INT8/16 performance since the update.
> nVIDIA wants to sell their crypto-p-oos and maybe they have introduced limiters in those fields in drivers, bios or both.
> 
> Any news on that?


There is no limiter being introduced with these BIOSes. If there was, would result in a huge class action lawsuit that NVIDIA would lose


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## Sora (May 6, 2021)

W1zzard said:


> There is no limiter being introduced with these BIOSes. If there was, would result in a huge class action lawsuit that NVIDIA would lose



probably wouldn't lose it actually, but they'd sure be spending money to win it and thats not worth it.

The drivers and any nvidia software intended to be run on a Geforce part are already distributed with a TOS dictating that no warranty is available for device or performance loss.



> 6. DISCLAIMER OF WARRANTIES AND LIMITATIONS OF LIABILITY
> 
> 6.1 No Warranties. TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, THE SOFTWARE IS PROVIDED "AS IS" AND NVIDIA AND ITS SUPPLIERS DISCLAIM ALL WARRANTIES OF ANY KIND OR NATURE, WHETHER EXPRESS, IMPLIED, OR STATUTORY, RELATING TO OR ARISING FROM THE SOFTWARE, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND NON-INFRINGEMENT. Without limiting the foregoing, Customer is solely responsible for determining and verifying that the SOFTWARE that Customer obtains and installs is the appropriate version for Customer’s model of graphics controller board, operating system, and computer hardware.
> 
> ...


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## W1zzard (May 6, 2021)

Sora said:


> probably wouldn't lose it actually, but they'd sure be spending money to win it and thats not worth it.
> 
> The drivers and any nvidia software intended to be run on a Geforce part are already distributed with a TOS dictating that no warranty is available for device or performance loss.


and no jury in this world would find it an acceptable excuse.

looks like nv's approach is to release new skus that are clearly marked as having a mining limiter


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