Catalyst says 1GB on a 512MB 4770? [Solved] Plus flickering on mem overclock

[jvroig]

Hey,

Just got myself this 4770 as a replacement for my aging 8600GTS. Two years ago, I got the 8600GTS for about $100. Got the 4770 for the same amount about a week ago. Pretty cool upgrade. I got this one, the one from PowerColor with Arctic Cooling PCS, 512MB GDDR5.

I installed Catalyst 9.12 (didn't bother using the one in the CD it came with).

Using CCC, I saw it effortlessly overclocks by a small amount (750MHz -> 830MHz), stable in FurMark (30 Mins) and playing Fallout 3 and Dragon Age at practically max settings on 1280x1024 for an extended period (4 - 6 hours).

However, I saw that Catalyst says my memory size is 1024MB. (and type is "HyperMemory"; I hope that means GDDR5 as it should be). That's weird, this should only have 512MB. Using Windows System Information, it also says I've got 1GB on my display adapter.

GPU-Z, however, seems to correctly report that I have 512MB of memory on my 4770.

Dragon Age config tool, correctly identifies my video card as a 4770, but also reports 1GB of memory on it.

What could be causing this?

Thanks.

I'm on Windows XP SP3, 4GB RAM (only 3.25 usable, of course).

 

[ExcaliburMM]

http://en.wikipedia.org/wiki/HyperMemory

 

[jvroig]

Ah, got it, thanks! From reading that as well as the AMD article it links to, I got the impression that it uses the video card's own memory first before touching the system RAM, I guess that's correct otherwise it would be slower.

Updated the thread title so I won't have to start a new one (lazy, sorry). I noticed that when I also overclocked the memory clock from 800 to 850 MHz through CCC, it resulted in a little flickering. It wasn't constant, but it was there. When I ran GPU-Z, I noticed that this flickering happens only when the clocks (GPU and Memory clock) seem to "reset". During periods of zero or minimal load, the clocks on the 4770 is 450MHz(GPU) and 800MHz (Mem). When it is loaded, it becomes the "normal" setting of 750/830MHz (830 when overclocked) and 850MHz (also overclocked).

Every now and then, however, even while just browsing the net or opening a new window to browse folders (and keeping GPU-Z refreshing in the background so I can monitor the load as I was tracing this problem), the clocks (which are naturally down to 450 and 800) would spike for a second to 830 and 850, then downclock back to 450 and 800 (GPU and mem). It is during that spike that the screen will flicker once or twice.

However, if I don't overclock the memory (so the clocks are 830 and 800), the spikes still happen as I still see them in GPU-Z sensors. But the screen doesn't flicker when they do happen. Even when it is a very minor overclock of the memory (800 to 815MHz, for example), the flickering still happens during the spikes.

Anybody care to enlighten me on what's happening here? Obviously, I have no idea here, and would appreciate any enlightenment you could spare.

Thanks.

 

[dflynchimp]

most likely the memory chips used in the 4770s is not drawn from the same bin as the higher-default-clocked 4870 cards, which doesn't mean that they are defective. It just means that they won't be clocking as high as what some of the 4870's can do. I'd just stick with a core overclock and be happy with that. Memory OCs don't usually add all that much performance anyways.

 

[Qbah]

It's a flaw of the first generation GDDR5 memory and the used voltage controllers. The memory runs full speed the whole time on the HD48xx series, doesn't downclock or overclock by default. It's because any voltage/frequency adjustments in real time cause the flicker on most cards. Unless you will force the memory to run at constant overclocked speed 24/7 or use ATT with shortcuts to forced speeds (only one flicker then, during transition, for example 2D or 3D fixed settings), you will experience the flickering. Because even if the card is idle it will sometimes go above low usage threshold (for whatever reason) and go into 3D clocks (which when overclocking cause them to go from stock 800 to OCed 830). Nothing you can do about it.

If it bothers you, I'd leave the memory stock or use ATT for having two profiles, 2D and 3D - and depending if you want to be on the desktop or play games, start the appropriate profile.

EDIT: That also applies to HD4770 as it of course uses GDDR5 too. And to elaborate, could edit the BIOS to have all 3 states (idle, UVD and 3D) fixed at the overclocked speeds to not have the card flicker when it goes into 3D (CCC doesn't touch the 2D and UVD modes, only 3D). Or use a tool like ATi Tray Tools (ATT) to force the mem on the card to run at OCed speeds.

 

[jvroig]

most likely the memory chips used in the 4770s is not drawn from the same bin as the higher-default-clocked 4870 cards, which doesn't mean that they are defective. It just means that they won't be clocking as high as what some of the 4870's can do. I'd just stick with a core overclock and be happy with that. Memory OCs don't usually add all that much performance anyways.

Thanks, yeah, I guess I'll leave it at default. I did experience some weirdness with the GPU clocks though, here.


@Qbah: Thanks, it did bother me so I just left it at default speeds. Thanks for the explanation, now I can finally start to not worry about it.