AMD Radeon 6870 PSU Question

benstat

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Hi all,
I've just installed an XFX Radeon HD 6870 graphics card, but I'm getting freezes and crashes in 3dmark and in games. I'm wondering if it's pushing my 550W PSU too hard. I have a Corsair VX 550 PSU, which is from their 'value' range (not sure if they still sell it, bought it in 2009).
I have an Intel i5 750 running at 2.66GHz (set to run in turbo mode, at 2.8GHz), a Gigabyte GA-P55A-UD4 motherboard, 2 * hard drives, 2* optical drives, 2 * Corsair 4Gb memory (8Gb total) and several USB devices.
Does this sound like a PSU issue? If so, what kind of wattage should I be looking for in a PSU (I thought about 650W because I'm unlikely to ever add Crossfire, or add any more hard drives etc).
Thank you in advance for your help!
Ben
 
Your PSU should be fine. It can handle up to 41 Amps on its single 12V rail, which is more than enough for the setup you described. Try installing something like MSI afterburner (works for almost any card) and monitoring temps and voltages on the card.

Also, you mentioned you've just installed the card. Was it an upgrade? If so, are you sure you properly removed the old drivers before installing the new card?

Also, does your computer present an error where your display driver stops working then recovers afterwards? If so, you may try setting your card's frequencies a little lower to see if its not faulty.
 

nordlead

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No, the 550 is fine and the VX550 can put out plenty of power on the 12V rail. AMD recommends a 500W PSU and you can crossfire on a 600W PSU if it has a high enough 12V limit. I wouldn't worry about the PSU unless you suspect it is bad.

However, with a bad PSU I wouldn't expect freezes, I'd expect complete system shutoff as the over current protection kicks in.
 

benstat

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Thanks very much for the info. Looks like you just saved me £70 on a PSU!

Yes, it was a direct replacement for an AMD Radeon 5770. I didn't uninstall the old driver first, but did install the latest Catalyst drivers (dated Oct 31st 2011).

When I run Dragon Age, for example, the game runs smoothly, but suddenly the screen freezes (no artifacts, it just stops dead). Sometimes it starts working again after a second or two, but after a few freezes the computer seems to hang. Interestingly, the mouse cursor is visible during one of these freezes, and it does move when you move the mouse.

3dmark has the same freezes, but after a few of them the screen goes blank with a kind of stripy vertical pattern on it. The only way to recover seems to be a reboot.

I use Win7 64 bit fwiw.

Thanks again,
Ben
 

benstat

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OK, thanks to you guys I might be getting to the bottom of this. I went into AMD OverDrive settings in Catalyst Control Centre to check the temperature (it was normal). However, I noticed that AMD OverDrive was enabled. I disabled it, and then tried again. It seems a lot more stable now!!



I have no wish to overclock my graphics card, and I don't remember ever enabling it (which is why I never thought to check it)! Stability is more important to me, and a 6870 at default settings should be more than adequate for games like Dragon Age and the upcoming Skyrim to run at ultra settings.

However, this raises another question. Am I getting the expected default performance from my 6870 with OverDrive disabled? I noticed it said the GPU and Memory clock speeds were both 300MHz (according to the meters). The OverDrive settings were 850Mhz for GPU, and 1200MHz for Memory (fan speed was left at auto).
 

benstat

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Fantastic!!!! Looks like problem solved then. If it's correct that AMD overdrive should be disabled by default for a 6870, then it looks like I can relax.

Thanks very much to everyone who posted. Without you help I suspect I'd have bought a new PSU, or returned the card and had the same problem with another one!

I'll keep an eye for any other comments and update the thread title to 'solved' shortly.
 

beenthere

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For the future -

If you want to objectively, accurately and scientifically determine what PSU power is required for your Vid card and PC in both watts and 12v rail amps., the forum Utility link below will show you how easy it is to calculate this information and objectively determine which PSUs are quality built, reliable PSUs that can meet your needs. Be advised that the available 12v rail amps. is just as important as the total PSU wattage. You need both to be correct.

http://www.tomshardware.com/forum/314712-28-please-read-determine-power-required
 

benstat

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Thanks, I might need that if I ever decide to Crossfire my new card with my old one. You never know, might happen if a decent enough game comes along...
 

benstat

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Oh, I see. Oops - newb mistake, sorry.

It's obvious to me what happened now.

I had an XFX AMD Radeon HD 5770. I upgraded to an XFX Radeon HD 6870, but I didn't uninstall the old drivers before installing the new ones. Normally that's an obvious thing to do, but I assumed that because they both use Catalyst that the drivers were probably the same anyway, so I just updated to the latest version.

Both the 5770 and 6870 DO have OverDrive enabled by default. Problem was that the 5770 had very different defaults to the 6870. Because I didn't uninstall the old driver, it simply kept the default 5770 OverDrive settings, which were way off for the 6870.

I realised this because I noticed a 'Default' button at the bottom of the OverDrive page. I clicked it, and OverDrive was then enabled with totally different settings for the 6870.

So now I have OverDrive enabled and it seems to work fine. Silly mistake really. Hope that helps another newbie in the same situation.
 
The kind of issue you described is typically happens on hardware failures on the GPU side. I get those when I overclock my GPUs. I advise you to run MSI afterburner, or even use catalyst's hardware configuration and underclock the card a bit. Test it at slower clocks with the same programs, if the issue goes away, then you have a defective card that can't handle stock speeds, and should e replaced.

EDIT: Heh, forgot to refresh the page, issue was already solved.
 

benstat

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Hehe, no frying pans, but I do use a few. I use a USB hub with a couple of USB software anti-piracy 'dongles' for audio software, a USB sound card, a USB MIDI keyboard, and finally a USB wireless mouse/keyboard receiver.

Actually, sounds like a lot now I mention it. Tried the PSU calc above but the link doesn't seem to work for me :-(