Intel Arc A770 Tested with PCIe 3.0 and Resizable BAR Off

[W1zzard]

In this article we're testing the Intel Arc A770 graphics card running at PCI-Express 3.0, to get a feel for performance on older systems that don't have the PCIe Gen 4 capability. Another round of testing is done with PCIe Resizable Bar disabled, and finally we have benchmarks on Gen 4 with ReBaR off.

Show full review

 

[wolf]

Wow, no wonder Intel basically flat out say if you don't have ReBAR, don't buy ARC.

 

[BSim500]

Ouch. That is all...

 

[Count von Schwalbe]

Interesting. A bit of a pity, actually, as many of the people looking at these would be those on a considerably low budget, possibly without a ReBAR capable machine.

 

[gridracedriver]

TERRIBLE

 

[DeathtoGnomes]

So comparable to a 3050.

 

[catulitechup]

@W1zzard very interesting review maybe can make a test with DXVK (mostly used for linux users and can play many DX9-10-11 titles) and works on windows too

Vulkan-based implementation of D3D9, D3D10 and D3D11 for Linux / Wine

GitHub - doitsujin/dxvk: Vulkan-based implementation of D3D9, D3D10 and D3D11 for Linux / Wine

Vulkan-based implementation of D3D9, D3D10 and D3D11 for Linux / Wine - doitsujin/dxvk

github.com

Maybe can make a test on linux

 

[Squared]

There aren't a lot of good options for PCIe 3.0 systems; every Nvidia card below the RTX 3060 and every AMD card below the RX 6700 support at most 8 PCIe lanes which means they suffer a performance hit on older systems. And the RTX 3060 and RX 6700 are rather expensive for an older computer. And older cards like the RX 5000 series and RTX 20 series are still pretty difficult to find at a price competitive with newer cards. So for people like me, still using an older Ryzen 1800X in a B350 board and an RX 480 graphics card, the Arc cards look really nice; much cheaper than the RTX 3060 but just as fast, and the DirectX 11 performance is fine because it's still better than my RX 480 which plays older games just fine; it's only in new (DirectX 12) games that I want better performance. But my system, like most PCIe 3.0 systems, doesn't support ReBar, so these Arc cards are just as bad an option (or maybe worse) than a card with 8 PCIe lanes. So I'll probably just never upgrade the graphics card in this computer.

Given that Nvidia and AMD handicapped the PCIe 3.0 performance of a lot of their GPUs, the future looks short for PCIe 4.0 graphics card slots, so I also won't be building a computer with an AMD X670 or B650 chipset which doesn't support PCIe 5.0 for the graphics card.

 

[lexluthermiester]

Ok, my take-away from this is that NoReBar depends on the game and the settings. Given that the A770 is playing right where Intel said it would(which handily shuts up the nay-sayers) and is competing with upper end cards(looking at you RTX2070/RTX3060), even without ReBar, it's still a good card.

@ Intel
Remember your audience and market. MOST of the people looking at this card will be on older systems and have no desire(or ability) to upgrade now or anytime soon. Fix your ReBar problems driver-side and be snappy about it. Then make the announcement that you have improved things to make these cards more appealing to a wider market sector. You've got a good thing going here. Make the most of it!

 

[wheresmycar]

A bit of a bummer for people on older non-rebar compatible hardware... but i have no problem with this. It's great to see INTEL competing in the GPU market! The only concern I have is the price... thats an easy fix which I'm sure Intel will entertain as we go along.

@ Intel
Remember your audience and market. MOST of the people looking at this card will be on older systems and have no desire(or ability) to upgrade now or anytime soon. Fix your ReBar problems driver-side and be snappy about it. Then make the announcement that you have improved things to make these cards more appealing to a wider market sector. You've got a good thing going here. Make the most of it!

I haven't looked to deep into all this rebar business. So essentially its a driver limitation? If correct, whats the reason behind limiting performance for older systems?

TERRIBLE

oh here we go!

 

[trsttte]

But my system, like most PCIe 3.0 systems, doesn't support ReBar, so these Arc cards are just as bad an option (or maybe worse) than a card with 8 PCIe lanes. So I'll probably just never upgrade the graphics card in this computer.

Check with your board manufacturer, there are both zen1 and b350/x370 boards with rebar active. If your board doesn't have the option try at least sending an email to the manufacturer support, these boards should still be supported with current agesa and if they're still issuing updates might be a matter of just un-hiding the option, either way can't really hurt.

And btw, pcie3.0 8x is fine (1-2% is margin of error).

Remember your audience and market. MOST of the people looking at this card will be on older systems and have no desire(or ability) to upgrade now or anytime soon. Fix your ReBar problems driver-side and be snappy about it. Then make the announcement that you have improved things to make these cards more appealing to a wider market sector. You've got a good thing going here. Make the most of it!

I think it's an architecture thing, they designed their memory controller with rebar in mind, not much can be done now around that. If your system is that old maybe you need more than a gpu upgrade anyway? (given that as I said above, boards as far back as b350/x370 have rebar support enabled).

 

[lexluthermiester]

So essentially its a driver limitation?

Not entirely. But if properly optimized, the drivers could smooth out the rough edges of the performance hit.

I think it's an architecture thing

That's part of it. There is always the hardware/software interface.

they designed their memory controller with rebar in mind, not much can be done now around that.

What Intel could do on systems without Rebar is invoke a system RAM caching scheme. It would be slower but effective and faster than without a cache. Such a scheme has been done in the past.

However, let's remember, even without ReBar, these card are still usable at 1080p and are a solid first go at the GPU market.

If I were AMD and NVidia I would be concerned if not worried.

 

[defaultluser]

So comparable to a 3050.

and these only cost 10 % more than this does on launch day:

ASRock Radeon RX 6700 XT Challenger D Gaming Graphic Card, 12GB GDDR6 VRAM, AMD RDNA2 (RX6700XT CLD 12G) - Newegg.com

Buy ASRock Radeon RX 6700 XT Challenger D Gaming Graphic Card, 12GB GDDR6 VRAM, AMD RDNA2 (RX6700XT CLD 12G) with fast shipping and top-rated customer service. Once you know, you Newegg!

www.newegg.com

https://www.bestbuy.com/site/nvidia-geforce-rtx-3060-ti-8gb-gddr6-pci-express-4-0-graphics-card-steel-and-black/6439402.p?skuId=6439402

looking to be really poor value fo anyone not having resizable bar (those cards are both 50% faster, when you add the bar plus pcie 3 hit)

then there's the 50% lower performance/watt to take us back to the absolutely roasting R9 390 surrounded by GTX 970 at s tepid 160w!

 

[wheresmycar]

Not entirely. But if properly optimized, the drivers could smooth out the rough edges of the performance hit.

good stuff! little improvements here and there as we go along is what i like to hear

 

[lexluthermiester]

and these only cost 10 % more

Your skills with math need improvement...

good stuff! little improvements here and there as we go along is what i like to hear

Like the driver devs at AMD & NVidia, the ARC driver dev team will refine, improve and optimize. It's in their best interests to do so.

 

[W1zzard]

What Intel could do on systems without Rebar is invoke a system RAM caching scheme. It would be slower but effective and faster than without a cache. Such a scheme has been done in the past.

Sorry but no, that's not how it works like at all.

Data is already in RAM, so no point making a copy to cache it in RAM. The problem is the 256 MB aperture with ReBAR off, which means all data has to get funneled through a small window

 

[Sabotaged_Enigma]

When could Intel ever learn to be humble?
Now the situation is, Intel have to optimise no-ReBAR system whether Intel want to do so or not.
With a product like this, they need to be humble enough to do enough optimisation to make it more competitive (yeah ray-tracing performance is pretty shiny by comparison).
Not to say this is a bad product or bad attempt, but certainly I won't be paying for this, just because I think they've got a lot more to do.

 

[RedBear]

There aren't a lot of good options for PCIe 3.0 systems; every Nvidia card below the RTX 3060 and every AMD card below the RX 6700 support at most 8 PCIe lanes which means they suffer a performance hit on older systems. And the RTX 3060 and RX 6700 are rather expensive for an older computer. And older cards like the RX 5000 series and RTX 20 series are still pretty difficult to find at a price competitive with newer cards. So for people like me, still using an older Ryzen 1800X in a B350 board and an RX 480 graphics card, the Arc cards look really nice; much cheaper than the RTX 3060 but just as fast, and the DirectX 11 performance is fine because it's still better than my RX 480 which plays older games just fine; it's only in new (DirectX 12) games that I want better performance. But my system, like most PCIe 3.0 systems, doesn't support ReBar, so these Arc cards are just as bad an option (or maybe worse) than a card with 8 PCIe lanes. So I'll probably just never upgrade the graphics card in this computer.

Given that Nvidia and AMD handicapped the PCIe 3.0 performance of a lot of their GPUs, the future looks short for PCIe 4.0 graphics card slots, so I also won't be building a computer with an AMD X670 or B650 chipset which doesn't support PCIe 5.0 for the graphics card.

While AMD and Intel claim that it's compatible only with series 500 motherboards, Resizable BAR, or SAM as AMD calls it, support was added with AMD AGESA 1.1.0.0 even to series 400 motherboards and it should work even with the series 300 ones now that many (most?) motherboards have belatedly received BIOS updates in order to enable Zen 3 compatibility. I would try to check it out with your motherboard manufacturer whether there's an update available and if it does enable ReBAR.

EDIT: Thinking about it, some tests done with PCIe Gen 3 + ReBAR on legacy Intel and AMD platforms could be interesting.

 

[AlwaysHope]

So the take away from this is if you want to use the full features of new generation cards like these new Intel dGPU cards then its best to have a newer generation system that is capable of resizable bar & at least 1 primary PCIe v4 graphics slot. Especially if gaming at 4k or 1440p with ultra settings.

 

[Crackong]

It is not a abug
it is a

 

[Forza.Milan]

so resizable BAR or SAM not for advantage anymore, but become requirement.. its more like athletes doing doping or they cannot running..

 

[Legacy-ZA]

so resizable BAR or SAM not for advantage anymore, but become requirement.. its more like athletes doing doping or they cannot running..

At least, for now.

Future releases, drivers/firmware updates may smooth things down the line. Time will tell. We might even see prices drop because of this.

 

[Shou Miko]

I am surprised that with ReSizeable Bar enabled the performance being PCI-E 3.0 or 4.0 is so close well done Intel

 

[lexluthermiester]

Sorry but no, that's not how it works like at all.

Damn, just a thought.

The problem is the 256 MB aperture with ReBAR off, which means all data has to get funneled through a small window

Perhaps that can be changed to something larger. 1024MB or 1536MB would likely help or even 4GB, assuming the aperture can be changed..

 

[W1zzard]

Perhaps that can be changed to something larger. 1024MB or 1536MB would likely help or even 4GB, assuming the aperture can be changed..

That's the definition of Resizeable BAR