i7-5775C: why did Intel abandon development of eDRAM?

[Shrek]

I stand corrected!

 

[Dr. Dro]

Sure, but how was it when it was new? I mean, modern games seem to be happy for large CPU caches, as it's demonstrated by Ryzen X3D CPUs.

I think if Intel pulled a similar move now, it would be way more appreciated than it was with the 5775C.

Agreed. The eDRAM had no major impact in the games of the time, so buyers heavily favored the faster clocking 4790K or the DDR4 capable 6700K instead. People who purchased the 5775C from the get go got the last laugh, but at this point, I mean, it's mostly academic anyway.

 

[80251]

It would be interesting to see how a i7-5775c would work with Fallout 4 and its excessively high volume of draw calls in downtown Boston.

 

[Toothless]

Agreed. The eDRAM had no major impact in the games of the time, so buyers heavily favored the faster clocking 4790K or the DDR4 capable 6700K instead. People who purchased the 5775C from the get go got the last laugh, but at this point, I mean, it's mostly academic anyway.

Some 5775c chips had good overclocking to match a 4790k in raw performance.

It would be interesting to see how a i7-5775c would work with Fallout 4 and its excessively high volume of draw calls in downtown Boston.

FO4 was one game with massive performance bumps. That's been tested years and years ago.

 

[Mussels]

Agreed. The eDRAM had no major impact in the games of the time, so buyers heavily favored the faster clocking 4790K or the DDR4 capable 6700K instead. People who purchased the 5775C from the get go got the last laugh, but at this point, I mean, it's mostly academic anyway.

In the benchmarks of the time, at least - no one monitored 0.1% lows back then

 

[Dr. Dro]

In the benchmarks of the time, at least - no one monitored 0.1% lows back then

Yeah, and most games still were targeting PCs that were about as powerful as the PS4 was, regardless. Up until 2014 or so we still had high-profile releases such as Borderlands Pre-Sequel releasing on DirectX 9 to appeal to the Windows XP holdout crowd. Such games couldn't really benefit from what the 5775C had on tap and the other CPUs didn't.

 

[Mussels]

Yeah, and most games still were targeting PCs that were about as powerful as the PS4 was, regardless. Up until 2014 or so we still had high-profile releases such as Borderlands Pre-Sequel releasing on DirectX 9 to appeal to the Windows XP holdout crowd. Such games couldn't really benefit from what the 5775C had on tap and the other CPUs didn't.

I'm playing that game right now, with the 4K texture pack the games visually alright - but oh boy you can sure tell it's not multi threaded, stacking certain effects just make the FPS go *splat* (especially the nvidia physx stuff, even with a 3090)

The people i'm playing with suffer a lot worse than i do with the x3D

 

[Tahagomizer]

Was your 9600k much faster than the i7-5775c at stock settings? The benchmarks Dr. Dro posted make it seem like the 5775c could probably beat out any Coffeelake CPU in certain games.

Probably not, at least didn't feel like it. I'm not an avid gamer and don't care about benchmarks so I didn't really quantify the difference. I also use a 3840x2160 screen since around the year 2015 so I was GPU limited anyway and made the change mostly because I wanted a mini-ITX motherboard with two m.2 NVME slots.

 

[AnotherReader]

In the benchmarks of the time, at least - no one monitored 0.1% lows back then

Techreport used to report on 99th percentile frame time, but their review of the 5775C is no longer available. Their revisit in 2018 is still available, albeit missing images, and it mentions that

Our testing at the time suggested that the i7-5775C’s eDRAM sometimes gave it an edge in 99th-percentile frame times versus the Core i7-6700K

 

[Wirko]

Techreport used to report on 99th percentile frame time, but their review of the 5775C is no longer available. Their revisit in 2018 is still available, albeit missing images, and it mentions that

Yes it is available! And actually still attributed to the right guy, the good Scott Wasson. The revisit you linked points to it, just the URL needs a small correction. It's actually a 6700K versus 5775C review, but sadly, far less useful without images.

Intel's Core i7-6700K 'Skylake' processor reviewed

techreport.com

 

[AnotherReader]

Yes it is available! And actually still attributed to the right guy, the good Scott Wasson. The revisit you linked points to it, just the URL needs a small correction. It's actually a 6700K versus 5775C review, but sadly, far less useful without images.

Thanks for the correction. The link from the revisit was broken.

 

[Nordic]

Agreed. The eDRAM had no major impact in the games of the time, so buyers heavily favored the faster clocking 4790K or the DDR4 capable 6700K instead. People who purchased the 5775C from the get go got the last laugh, but at this point, I mean, it's mostly academic anyway.

I am a little late to this thread but the 5775C absolutely had double digit performance increases in many games. I desperately wanted one to replace my 4770k but they could not be found. AMD's x3d cache is far more advanced and a better implemenation in general but it doesn't beneifit every game either. Not every application, game, or workload actually benefits from a larger cache. Some games like Borderlands 3 as shown in TPU's reviews had as high as a ~43% increase in performance over the 5800x. Other games like RDR2 had gains 2.4% over the 5800x which might as well be margin of error.

The other difference is that edram is slow and does not work as well as a cache as AMD's x3d cache. Earlier in the thread I saw that @AnotherReader showed a Chips and Cheese graph. They did not link the whole article which was a great read. https://chipsandcheese.com/2023/04/23/amds-7950x3d-zen-4-gets-vcache/

Intel has the IPC advantage over AMD. If Intel were to implement even a slow edram cache again, they would be the defacto king of gaming.

 

[AusWolf]

All this talk made me want to build a system around one of these rare gems. I found a processor for 80 quid (it isn't cheap), but used Z97 motherboard prices are through the roof! Oh man.

 

[LabRat 891]

All this talk made me want to build a system around one of these rare gems. I found a processor for 80 quid (it isn't cheap), but used Z97 motherboard prices are through the roof! Oh man.

I ALMOST did the same, but I already have at least half a dozen 'backlogged' parts-on-hand retro builds. I didn't need another.
Admittedly, the eDRAM-Broadwell is a 'curio' worthy of owning (and a gap in my collection). However, both its performance and 'place'(Win8.1-10) is modern enough that I feel my main Zen 3 machine 'covers it'.

While 'not the same, at all, actually', conceptually Zen3DVcache took up the mantle of what eDRAM was accomplishing. I'm much more inclined to spend money on an AM4 5800X3D than a curio from Intel.

As to looking for a board...
While not OCable, single-socket 'server'/'workstation' boards using C222, C224, C226 chipsets (if compatible) will be stable and long-lasting. Every once in awhile, you can find someone liquidating or retiring that kind of kit. In my experience, it's more common to 'find a deal' on retired server kit than anything ever marketed towards Enthusiasts/OCers/Gamers.

The other option (which are often neither stable or OCable) are 'China-source' motherboards using Z97 or H97 chipsets. They're often '(re)built' around eWaste PCHs, and have varying levels of features and functionality. They are usually much cheaper than 'enthusiast kit' on eBay, though.

On the CPU, I'm not sure if it's as unique as we think it is.
I suppose this could be incorrect or 'incorrect, in context' but at least according to wikipedia, most Iris (Pro)-supporting Intel CPU products utilized eDRAM. edit: see @Fouquin 's post, below mine.

 

[Fouquin]

Also, isn't the 5775C that weird mutant with an AMD iGPU? I bet licensing wasn't flawless.

No, that's Kaby Lake-G.

Interestingly I didn't see anyone mention that Skylake did still utilize eDRAM, but that the implementation had changed from being L4 cache to being addressed as DRAM through SA. Consumer chips with eDRAM appeared as Skylake-R.

From AnandTech:

"Rather than acting as a pseudo-L4 cache, the eDRAM becomes a DRAM buffer and automatically transparent to any software (CPU or IGP) that requires DRAM access. As a result, other hardware that communicates through the system agent (such as PCIe devices or data from the chipset) and requires information in DRAM does not need to navigate through the L3 cache on the processor. Technically graphics workloads still need to circle around the system agent, perhaps drawing a little more power, but GPU drivers need not worry about the size of the eDRAM when it becomes buffer-esque and is accessed before the memory controller is adjusted into a higher power read request. The underlying message is that the eDRAM is now observed by all DRAM accesses, allowing it to be fully coherent and no need for it to be flushed to maintain that coherence."

 

[AusWolf]

I ALMOST did the same, but I already have at least half a dozen 'backlogged' parts-on-hand retro builds. I didn't need another.
Admittedly, the eDRAM-Broadwell is a 'curio' worthy of owning (and a gap in my collection). However, both its performance and 'place'(Win8.1-10) is modern enough that I feel my main Zen 3 machine 'covers it'.

While 'not the same, at all, actually', conceptually Zen3DVcache took up the mantle of what eDRAM was accomplishing. I'm much more inclined to spend money on an AM4 5800X3D than a curio from Intel.

As to looking for a board...
While not OCable, single-socket 'server'/'workstation' boards using C222, C224, C226 chipsets (if compatible) will be stable and long-lasting. Every once in awhile, you can find someone liquidating or retiring that kind of kit. In my experience, it's more common to 'find a deal' on retired server kit than anything ever marketed towards Enthusiasts/OCers/Gamers.

The other option (which are often neither stable or OCable) are 'China-source' motherboards using Z97 or H97 chipsets. They're often '(re)built' around eWaste PCHs, and have varying levels of features and functionality. They are usually much cheaper than 'enthusiast kit' on eBay, though.

Actually, it's those China-originated Ebay motherboards that made me rethink the project, as they're going for £2-300 plus postage, which is insane. Combine that with the price of the CPU, and I could've upgraded my 7700X to a 7800X3D instead. I love curiosity builds, but this is not worth it, even for me.

No, that's Kaby Lake-G.

Interestingly I didn't see anyone mention that Skylake did still utilize eDRAM, but that the implementation had changed from being L4 cache to being addressed as DRAM through SA. Consumer chips with eDRAM appeared as Skylake-R.

View attachment 297585

From AnandTech:

"Rather than acting as a pseudo-L4 cache, the eDRAM becomes a DRAM buffer and automatically transparent to any software (CPU or IGP) that requires DRAM access. As a result, other hardware that communicates through the system agent (such as PCIe devices or data from the chipset) and requires information in DRAM does not need to navigate through the L3 cache on the processor. Technically graphics workloads still need to circle around the system agent, perhaps drawing a little more power, but GPU drivers need not worry about the size of the eDRAM when it becomes buffer-esque and is accessed before the memory controller is adjusted into a higher power read request. The underlying message is that the eDRAM is now observed by all DRAM accesses, allowing it to be fully coherent and no need for it to be flushed to maintain that coherence."

That's interesting to know, thanks!

 

[LabRat 891]

Actually, it's those China-originated Ebay motherboards that made me rethink the project, as they're going for £2-300 plus postage, which is insane. Combine that with the price of the CPU, and I could've upgraded my 7700X to a 7800X3D instead. I love curiosity builds, but this is not worth it, even for me.

Holy crap, things have changed in a year or two. Yes, that is insane.
At those prices, not worth it. (Most of my Retro Kit, Curios, and Relics have been piecemeal'd 'deals' off eBay or long-ago collected salvage.)

 

[Wirko]

So only in the two IBM z15 chips the eDRAM is actually embedded. That is, made on the same die, with the same technology, as the cores and other logic. The chip sizes are extreme here, 700 mm2 for the chip with processor cores.

IBM Introduces Next-Gen Z Mainframe: The z15; Wider Cores, More Cores, More Cache, Still 5.2 GHz

IBM introduces its latest Z mainframe, the z15. Here's a detailed look at the changes and enhancements that were made including the new system architecture and CPU microarchitecture.

fuse.wikichip.org

 

[Dr. Dro]

I am a little late to this thread but the 5775C absolutely had double digit performance increases in many games. I desperately wanted one to replace my 4770k but they could not be found. AMD's x3d cache is far more advanced and a better implemenation in general but it doesn't beneifit every game either. Not every application, game, or workload actually benefits from a larger cache. Some games like Borderlands 3 as shown in TPU's reviews had as high as a ~43% increase in performance over the 5800x. Other games like RDR2 had gains 2.4% over the 5800x which might as well be margin of error.

The other difference is that edram is slow and does not work as well as a cache as AMD's x3d cache. Earlier in the thread I saw that @AnotherReader showed a Chips and Cheese graph. They did not link the whole article which was a great read. https://chipsandcheese.com/2023/04/23/amds-7950x3d-zen-4-gets-vcache/

Intel has the IPC advantage over AMD. If Intel were to implement even a slow edram cache again, they would be the defacto king of gaming.

It did. I had one myself. But between its very contextual performance uplifts and incompatibility with Z87, plus the 6700K existing really put it in a tight place

 

[Veseleil]

incompatibility with Z87

So there's no hope for my GA-Z87X-UD5H to ever fit one of these?

 

[Dr. Dro]

So there's no hope for my GA-Z87X-UD5H to ever fit one of these?

Nope, there is not. The i5-5675C, i7-5775C and Xeon E3 v4 counterparts will only boot on H97 or Z97 chipset motherboards. In Broadwell, some pins that were formerly reserved on the Haswell LGA were remapped and used (likely due to different FIVR revision and presence of the eDRAM die), rendering the original 8 series chipsets incompatible.

It's a shame, I had a very nice ASUS Sabertooth Z87 back then. Thing was built like a tank, I bet it's still in someone's PC somewhere after all these years.

 

[Veseleil]

Nope, there is not. The i5-5675C, i7-5775C and Xeon E3 v4 counterparts will only boot on H97 or Z97 chipset motherboards. In Broadwell, some pins that were formerly reserved on the Haswell LGA were remapped and used (likely due to different FIVR revision and presence of the eDRAM die), rendering the original 8 series chipsets incompatible.

It's a shame, I had a very nice ASUS Sabertooth Z87 back then. Thing was built like a tank, I bet it's still in someone's PC somewhere after all these years.

Good Z97 boards are over 100€ around here, so I guess I may as well stop thinking about 5775C project from now on. Not worth it, same as buying a 4790K at this point (my z87 has an 1241v3 installed).

 

[Dr. Dro]

Good Z97 boards are over 100€ around here, so I guess I may as well stop thinking about 5775C project from now on. Not worth it, same as buying a 4790K at this point (my z87 has an 1241v3 installed).

They are sooo expensive... I ended up selling my 5775C when my ASUS Z97M-PLUS "died". Basically all of the memory slots except the rightmost stopped working on it. Not a good board by any means, but even replacing that cheap board didn't make any financial sense. But you aren't missing much, for example, the integrated graphics don't work on Windows 10, plugging anything on the HDMI port caused the machine to instantly BSOD. It was that bad. But hey, Quick Sync Video worked and it worked well.

If you mean to have some fun with a peculiar socket 1150 chip, I recommend you pick up a Pentium G3258. It's very fun to overclock and see how far you could push a pure dual-core.

 

[AusWolf]

Good Z97 boards are over 100€ around here, so I guess I may as well stop thinking about 5775C project from now on. Not worth it, same as buying a 4790K at this point (my z87 has an 1241v3 installed).

Same thoughts here (especially since I'm in the middle of working on a 7700K nostalgia build). But it's sooo tempting!

 

[Veseleil]

Same thoughts here (especially since I'm in the middle of working on a 7700K nostalgia build). But it's sooo tempting!

Tbh, I'd like to have two identical motherboards, one with 4790k, and the other with 5775c. Overclocking both and comparing them across multitude of workloads would be so fun.