[NattyKathy]

I was curious just how limited tuning is on these cards and

Holy crap that's bad. Max allowed mem clock 18.5GT/s effective, max allowed core clock 2803Mhz :-O Lowest I've seen yet for RX 7000 series.
Not much point sticking an EVC on one of these, the clock limits will get ya before voltage limit.

VBIOS editing for 7000 series when?! (yeah I know- never.)

 

[NattyKathy]

I've been really irritated by the reviews, seems like noone has tried to overcome the clock disadvantages of the GRE when the specs on paper alone should net more than a 13% improvement over the 7800xt. Though seems like AMD has really handicapped it. It is bound to have some OC headroom with those anemic clocks, coupled with an increase power envelope (if an AIB will make it happen) and we should see 20% over the 7800xt I would think.

They can't overcome the clock disadvantage because the core clocks are locked at 2803Mhz max. The slider apparently doesn't go any further. And only 2316Mhz/18.53GT/s is allowed for the VRAM :-(

Looking at the TPU Nitro+ 7900GRE review linked a couple posts up, the new AiB models allow over 300W TBP- up to 355W for the Nitro+. And they did basically max out the clocks within what's possible, 2747Mhz on the Nitro and I see they got a Steel Legend GRE up to 2802Mhz which is right at the limit.

The problem here is the limited VRAM/Core clock adjustments allowed by AMD and there's currently no way to get around those on RX 7000-series.

Edit to add- and the 256-bit VRAM bus ofc. Combined with the low mem clocks, the GRE has only ~70% the bandwidth of the 7900XT and even slightly less bandwidth available than the 7800XT.

 

[NattyKathy]

Has anyone tried to see if the 7900XT bios can work on it? I remember back in the day AMD tried to do this with Vegas56, people just flash the Vegas64 bios on it and gained back the GPU and VRAM clocks.

I don't think that works anymore. I tried flashing my 7900XT with an XTX BIOS (using a hardware programmer) to get around power and voltage limits, but no matter which XTX BIOS I tried the AMD driver threw an error and refused to load and with some XTX BIOS the system wouldn't even boot.

I think 5700->5700XT was the last time crossflashing was possible on AMD because I havent found any reliable info about it being done on 6000-series either.

 

[NattyKathy]

Oh wow, I guess it's really locked down now.

Yeah AMD has very much locked down the VBIOS on RX 6000/7000. There's now checks similar to how NV has locked down their VBIOS, except unlike with NV there's no leaked exploit to bypass the checks.

Afaik the RedBIOSEditor team has straight-up just given up on these cards which says a lot.

Not a huge deal for 7800XT / 7900XT / 7900XTX since AMD has been generous with the frequency ceilings for those and EVC can bypass voltage & power limits, but for other 7000-series cards there's a hard clockspeed cap that may never be bypassed.

 

[NattyKathy]

Necro bump because I'm really curious about how the GRE would perform with this this procedure:

https://www.overclock.net/posts/29459382/

It's a full die and has weirdly low current limits, it could benefit a lot from extra current. Could be a sleeper card with this method.

No matter what's done with power/current limits, the low clock limit is going to continue to be a barrier unfortunately.

 

[NattyKathy]

GPU or VRAM clock? Is the limit at driver or bios level?
Have a look at 7900XT current limits

View attachment 2710136

For Core/SoC/USR, at least they're in hwinfo list. Now look at 7900GRE:

View attachment 2710137

That's quite the difference. There's also two other rails that don't have limits mentioned in hwinfo, Vmem and Vddci but last one doesn't matter that much. You can now offset the current for all these rails.
I was able to get my (7800XT) VRAM to 2850MHz, benchmarked at that speed, and seemed to pass memtest_vulkan 5 minutes test at 2800MHz, though I'd back off a bit, 2750MHz or so. LLMs were fine in a short test I made.
If software allows setting 2800MHz then it will probably work at that speed provided you offset the current to help with that.

Looking at TPU OC results in their reviews, they were able to get GRE right up to the 2800Mhz limit in-game which is why I'm thinking power is not the primary limiting factor.

Raising limits with EVC could eke out a little more performance in some high-power applications but it won't be anything like 7900XT where EVC can be the difference between 2900Mhz (power-limited) and 3200Mhz or even 3400-3500 for benching. The GRE is just too clock-limited and it's too bad because you're right that otherwise it could be a strong contender for OC.

 

[NattyKathy]

But Vcore has exactly 50% less current limit vs 7900XT. That has to play into it barely reaching 2800MHz. I doubt it has some kind of weird BIOS clock limit.
Curious how LACT interface looks on Linux, for 7900GRE, does it allow setting clock higher than 2800MHz? Like 3300MHz for example?
The low clocks could simply be enforced with a low current limit, or VI curve. I'd certainly try the current gain mod if I had one.

It does appear to have a weird BIOS limit unfortunately. Radeon Overdrive limits have been stored in VBIOS for a long long time; one used to be able to bypass them with registry PowerPlayTables but AMD has locked down / removed that capability on newer cards.

Here are 7900GRE HWBot results including submissions from some of the best OC'ers in the world and not one of them got past the 2.8Ghz limit 😕
AMD Radeon RX 7900 GRE @ HWBOT
Fwiw it's the same situation with 7600 (3Ghz limit) and 7600XT (3.2Ghz limit) and afaik those have not been bypassed either.

I'll do some digging on Discord but I do believe EVC has been tried on GRE.
I'm not saying the current limit is irrelevant, but I am saying there is a lot of evidence that even if one were to raise PL the card wouldn't go over 2.8Ghz.

 

[NattyKathy]

Yeah they don't seem to clock higher, but also no mention of EVC2SE on any of them.
Could be a stupid idea but anyone tried XT BIOS on GRE?

Crossflashing to different models is blocked on RDNA3 sadly. I tried flashing my XT with various XTX bios and driver refused to load.