Wednesday, June 16th 2021

AMD Radeon RX 6900 XT LC Specs Confirmed: 12% Higher Core and Memory Clocks, 10% Higher Power

A leaked SKU sheet posted to Twitter by VideoCardz confirmed that AMD is indeed positioning the Radeon RX 6900 XT Liquid Cooled (LC) as a SKU separate from the RX 6900 XT. The finalized specs reveal that the card features Game Clocks of 2250 MHz, compared to 2015 MHz of the stock (air-cooled reference) RX 6900 XT; while the memory now operates at 18 Gbps (GDDR6 effective), compared to 16 Gbps on the reference card. This gives the GPU a memory bandwidth of 576 GB/s, compared to 512 GB/s on the reference. To support these, the TBP (total board power) value is increased by 10%, and is now at 330 W, compared to 300 W on the reference RX 6900 XT. The RX 6900 XT LC lugs an all-in-one, closed-loop, liquid cooling solution, while drawing power from the same two 8-pin PCIe power connectors as the original RX 6900 XT.
Source: VideoCardz (Twitter)
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35 Comments on AMD Radeon RX 6900 XT LC Specs Confirmed: 12% Higher Core and Memory Clocks, 10% Higher Power

#26
watzupken
Kohl BaasBecause you most likely base your assumption on single loop custom watercooling which is a highly unbalanced solution for a GPU. The GPU is fine and dandy with the water temp hitting 55°C, while a single loop in most case must top at 35°C in order to keep the less tolerand CPU cool enough. Assuming a 25°C room temperature, a 120mm radiator running on 55°C water dissipates as much heat as a 360 radiator on 35°C water.

I used to play with these stuff in my loops in order to achieve as much silence as possible without the need for oversizing the radiators.
If I am going for low noise, I think I would prefer a bigger radiator because 2x fan running at lower RPM is going to be less noisy than a single 120mm fan running at high RPM. I would consider a 120 AIO only if there's space constraints.

Anyway, it is good to know that the 120mm AIO will be sufficient to cool the GPU. I believe AMD would have tested it anyway to make sure that the cooling is sufficient before they approve this setup.
Minus InfinityImagine how well Navi 21 would have performed if they didn't gimp the bus width. 256 bit and they wonder why oit goes from easily having the 1440p crown to getting beaten in 4K. Let's hope Navi 31 doesn't get the gimp treatment too.
A wider memory bus would have a positive impact to 4K performance, but not sure by how much. It will also make the chip bigger, more power hungry and hotter at the same time. That is where the Infinity cache is supposed to help. I suspect if we remove the core clockspeed bump on this XTX variant and just compare performance improvement @ 4K with just the improved memory clockspeed, I think the performance improvement is going to be quite small. The RTX 3070 Ti is a classic example where the even the GDDR6X failed to deliver any tangible performance gain. I believe its mostly because of the increase in CUDA cores that contributed to the 7 to 8% gains.

In my opinion, the main reason why AMD is less competitive at 4K resolution is not because of the memory bandwidth, but because Nvidia hardware thrives at higher resolution. At 1080p and 1440p, the high end cards like the RTX 3080 is more CPU bound than AMD's RX 6900/6800 series. So they tend to end up slower/ not so competitive. At 4K, the GPU becomes the bottleneck, and that's where the hardware shines/ able to stretch their leg and overtake AMD.
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#27
turbogear
GhostRyderIts funny, cards are in stock on newegg being sold by newegg, but they are at scalper prices.

I wonder how well these XTX variants will clock
The XTXH variants has been around for 2 months.
They were launched before 3080Ti. :rolleyes:
I bought mine mid of April. Multiple non reference designs were launched in April including PowerColor, Sapphire etc.
I have the PowerColor 6900XTU Liquid Devil Ultimate.
This XTXH card comes with EKWB water block factory fitted.

I have been running it at 2750MHz@1175mV since a while.
Note: Max core voltage can be set to 1200mV. So I have it undervolted and OCed.
It boosts up to 2705MHz in games. In Cyberpunk it sustains that frequency almost all the time.:D
I don't use Raytracing though.

The power target for GPU core is set by me to 415W and TDC to 400A using MPT. So total power allowed at the moment on my card is 460W icluding power from other components on GPU.:laugh:

Mine can be pushed to 525W being 3x8 pin card.
As far as I know this reference XTXH card is coming only with 2x8pin PCIe power connector.
With current setting, in games the core power consumption though remain in range 330W-350W.
My Time Spy score is around 21415 without memory OC. I am not OCing memory so default GPU memory bandwidth is used.

Note: PowerColor already by default allows 382W core power and 368A TDC on performance bios talking into account 15% slider setting in Radeon SW i.e. default performance bios setting is 332W core power and 320A TDC which can be increased by 15% in Wattman.

This reference LC XTXH model with one 120mm radiator would be good at specified frequency, but I cann't image this being pushed to performance level that I can operate mine without overheating in stress tests.

With setting I have even with my big loop with 3 radiators in total making 2x360mm radiator space the hotspot temperatures was hitting 92°C in stress tests at 415W core power. I have 6900XTU and 5900X in the loop.

I had to change the TIM to Liquid Metal and now the hotdpot temperatures in stress situations remain below 78°C. :)
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#28
Pixrazor
This won't be cheap, just overclock the 6900xt to have similar performance or even the 6800xt.
Posted on Reply
#29
turbogear
PixrazorThis won't be cheap, just overclock the 6900xt to have similar performance or even the 6800xt.
Basically XTXH is not new chip.
These are 6900XT which are higher binned so garantied to be OCed higher.
At least that's what PowerColor promises for their two XTXH cards.
I don't know about other brands if they also promise something like that for their XTXH cards.
www.powercolor.com/new?id=1618371606
With the PowerColor RED DEVIL ULTIMATE and LIQUID DEVIL ULTIMATE cards, you remove the element of chance and guarantee a specially binned GPU with exceptional overclocking – PowerColor assures performance every time.
With regular 6900XT it is more like silicon lottery.
If one is lucky then one gets a great OCing 6800XT or 6900XT cards but there in promises there.

I had two regular 6900XT in my hands (6900XT Red Devil and Sapphire Toxic LC) and with both cards I was not lucky and they could not be OCed above 2600MHz and for that range also you needed more than 400W on GPU core. :oops:
So only got me about 4% higher performance than my damn good 6800XT reference while consuming about 70W more.
I don't own any of these anymore as I was looking for good Ocing 6900XT.

I had two 6800XT in the past.
The refernce 6800XT was my first RDNA2 card bought in November last year and it was really damn good Ocing chip. I ran it at 2750MHz@1020mV. :D
Unfortunately my that 6800XT reference got damaged with ESD issue. :cry:
To replace that damaged card, I got 6800XT Red Devil and this was the worst of all. I could not go higher than 2400MHz. Set anything higher and it would start stuttering and crashing.:fear:
I returned it within 14 days German return rights. :p

I would not have bought 6900XTU Liquid Devil Ultimate if I still had my reference 6800XT which was a dream card which OCed very well under water and while power target for 2750MHz@1020mV was only 280W + 15% for gpu core and it ran like a champ.

So from my experience I was only lucky ones in 4 trials. :laugh:

Somehow from the owner's club if I kind of look at statistics, it looks like the early batches of 6800XT reference and custom cards were really good for Ocing.
Posted on Reply
#30
Krzych
maxitaxi96A single 120mm rad for 330Watts? AMD, are you guys insane??? I get the whole SI and OEM compatibility stuff... but still... that fan will have to spin like crazy...
Also it's not like a 240mm aluminium rad is THAT much more expensive compared to a 120mm, especially not for manufacturers.

Why even bother to watercool it?
This is actually not that bad, 120mm AIO can take a lot. I was running overclocked 380W 2080 Ti on 120mm AIO for 2 years with no issues and it needed hot summer to go into 60s. I even put it in a room with 42C ambient temp and no ventilation just to see how bad can it get and it stabilized at like 74C, so it will have no problems cooling some funny 330W stock. You could put 120mm AIO on 525W overclocked RTX 3090 even. Assuming that ugly 3.5-slot bricks are not your thing and you don't want to go custom LC, this is what you get. These type of cards are always rather niche, but they are okay.
Posted on Reply
#31
turbogear
KrzychThis is actually not that bad, 120mm AIO can take a lot. I was running overclocked 380W 2080 Ti on 120mm AIO for 2 years with no issues and it needed hot summer to go into 60s. I even put it in a room with 42C ambient temp and no ventilation just to see how bad can it get and it stabilized at like 74C, so it will have no problems cooling some funny 330W stock. You could put 120mm AIO on 525W overclocked RTX 3090 even. Assuming that ugly 3.5-slot bricks are not your thing and you don't want to go custom LC, this is what you get. These type of cards are always rather niche, but they are okay.
That would be interesting to see when somebody who owns this card and try to push it to that high OC. :rolleyes:

I agree 120mm would not have any issue by cooling 330W, but let's see if one can push this to above 400W with only one 120mm radiator without card starting to throttle at very high OC.

My experience with XTXH and also what I read from other owners of 6900XT XTXH cards is that the card needs decent amount of cooling to push it to very high frequencies with high power target.

On my 6900XTU Liquid Devil Ultimate and 2x360mm radiator space I already hit 92°C on hotspot temperature under stress tests with 22°C room temperature at my 2750MHz@1175mV at 415W power target.
After putting Liquid Metal on the Die, I got now hotspot temperatures maxing at 78°C.
This is hotspot temperatures but of course GPU temperatures are about 12°C below that and lie in the range of 66°C.
On AMD GPUs as far as I know hotspot is important and GPU starts to throttle as temperatures go higher than 100°C.
Posted on Reply
#32
GhostRyder
turbogearThe XTXH variants has been around for 2 months.
They were launched before 3080Ti. :rolleyes:
I bought mine mid of April. Multiple non reference designs were launched in April including PowerColor, Sapphire etc.
I have the PowerColor 6900XTU Liquid Devil Ultimate.
This XTXH card comes with EKWB water block factory fitted.

I have been running it at 2750MHz@1175mV since a while.
Note: Max core voltage can be set to 1200mV. So I have it undervolted and OCed.
It boosts up to 2705MHz in games. In Cyberpunk it sustains that frequency almost all the time.:D
I don't use Raytracing though.

The power target for GPU core is set by me to 415W and TDC to 400A using MPT. So total power allowed at the moment on my card is 460W icluding power from other components on GPU.:laugh:

Mine can be pushed to 525W being 3x8 pin card.
As far as I know this reference XTXH card is coming only with 2x8pin PCIe power connector.
With current setting, in games the core power consumption though remain in range 330W-350W.
My Time Spy score is around 21415 without memory OC. I am not OCing memory so default GPU memory bandwidth is used.

Note: PowerColor already by default allows 382W core power and 368A TDC on performance bios talking into account 15% slider setting in Radeon SW i.e. default performance bios setting is 332W core power and 320A TDC which can be increased by 15% in Wattman.

This reference LC XTXH model with one 120mm radiator would be good at specified frequency, but I cann't image this being pushed to performance level that I can operate mine without overheating in stress tests.

With setting I have even with my big loop with 3 radiators in total making 2x360mm radiator space the hotspot temperatures was hitting 92°C in stress tests at 415W core power. I have 6900XTU and 5900X in the loop.

I had to change the TIM to Liquid Metal and now the hotdpot temperatures in stress situations remain below 78°C. :)
I am aware that some had been released already, I was more referencing these specific variants.

You have the one I really want, just dont want to pay these ridiculous prices. I want to be able to just push it way over the top and see how it does in my loop. I am planning on doing a new build once I get one of these cards.

With yours pushed so hard, I would love to see what it would do in some benchmarks. I need to lookup one of those reviews on one as I have not yet.
Posted on Reply
#33
spnidel
dicktracyStill slow with DXR. Nothing can save them except for a new architecture.
still at it with the blatant shill-like goalpost moving? how much do they pay you?
Posted on Reply
#34
ltkAlpha
Whether or not the cooling solution will cope with the wattage is only part of the picture. What you're doing when choosing to go with 120mm AIO to cool a 350W GPU vs a good air cooler is sacrificing price, leakage risk and sound levels to produce marginally better cooling performance and improve case air temps. (I would also be curious to see what water temps and water permeation into the tubes are going to be with prolonged use). I've water-cooled a 980 Ti with a 140mm AIO (Arctic had a model) and a Noctua fan (audible) and I'm currently running a 1080 Ti under a NZXT G12 and Kraken X53 (?) 240mm (quiet) and I would bet good money that the 6900 XT LC will have to go loud under load to cope, especially given the fact that the fan is going to be exposed however you mount the AIO. IMO, this is not the type of trade-off enthusiast users should be expected to accept when buying a 1000+ dollar product given the high quality of air coolers already on the market. The Sapphire TOXIC RX 6900 XT Limited Edition I can understand, but this product? Who is this for?
Posted on Reply
#35
turbogear
GhostRyderI am aware that some had been released already, I was more referencing these specific variants.

You have the one I really want, just dont want to pay these ridiculous prices. I want to be able to just push it way over the top and see how it does in my loop. I am planning on doing a new build once I get one of these cards.

With yours pushed so hard, I would love to see what it would do in some benchmarks. I need to lookup one of those reviews on one as I have not yet
I am not Ocing the GPU memory at the moment.
Without memory OC, I get around 21400 Time Spy score with 2750MHz@1750mV. :D

I tried to go higher. I could reach 2800MHz in Heaven benchmark but that's not stable in Time Spy but 2750MHz@1175mV is very stable.
2800MHz could be possible to reach stabily with giving higher than 415W to GPU core and TDC higher than 400A but the GPU was expensive (2199€) and I did not wanted to risk it. :oops:

Here is the post with some results which I posted initially as the later attempt for higher frequency than this failed the Time Spy in here is still same range:
www.techpowerup.com/forums/threads/the-rx-6000-series-owners-club.276164/post-4504149

In above post I mentioned that I wanted to change my PSU. It was replaced with Bequiet 1200W Dark Power Pro 12 Titanium.

Maybe this weekend I can run some new benchmarks (Time Spy/ Fire Strike) with memory oc.
With a 2120MHz memory frequency expected result would be in range of 21800-21900 Time Spy.

It is on my todo list since some time but spent too much time trying reach 2.8GHz last weeks that I stopped to spend some time on real gaming. :laugh:
Now last week kind of busy with football as we have UEFA Euro ongoing and I am a football fan. :p
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