Help! HD 6950 crashes computer after starting game

[martin.c.dean]

Hi everyone,

Having some issues with a Sapphire 11188-05-50G HD6950 Graphics Card (2GB, GDDR5) - Dirt 3 edition

I had a few issues installing - I uninstalled old drivers, shut down, put in new card, restarted, installed new drivers - and the screen went black.

This appeared to be resolved when I installed the new drivers from the manufacturer's website in safe mode.

I played Skyrim happily for 2 hours - and then then monitor went off, and the system froze. Had to do a hard reset.

Now, the computer starts ok, (mostly - occasionally the monitor won't power up and I have to reset again.) But every time I try to run Skyrim, the game gets to the Load Game menu and the same thing happens. Monitor goes off, system freezes.

I have a 500w power supply, which is what the card says it needs

I've plugged it in using 1 molex to 6 pin that was powering the previous card, and from another molex that was free that wasn't being used before. Are there specific molex's I should run the second 6 pin from?

My system specs are below - any help gratefully received.



Operating System
MS Windows XP Professional 32-bit SP3
CPU
Intel Core 2 Duo E6550 @ 2.33GHz 45 °C
Conroe 65nm Technology
RAM
4.00 GB Dual-Channel DDR2 @ 400MHz (5-6-6-31)
Motherboard
ASUSTeK Computer INC. P5N-E SLI (Socket 775) 40 °C
Graphics
Sapphire 11188-05-50G HD6950 Graphics Card (2GB, GDDR5)
Hard Drives
488GB SAMSUNG SAMSUNG HD501LJ (ATA) 30 °C
Optical Drives
Virtual CDROM 0CF320FF USB Device
ATAPI DVD A DH20A4P
POLMT 349UB05 SCSI CdRom Device
Generic DVD-ROM SCSI CdRom Device
Audio
Realtek High Definition Audio

 

[Wuzup101]

What was the previous card? Did you ever have any problems using that card that would indicate that it could have been a pre-existing problem?

A quality 500 watt power supply should provide enough power for a 6950 and a C2D without issue. That being said, not all power supplies are created equal. What type of power supply do you have? Do you know if it has a single or multiple 12 volt rails? If it has multiple rails, there is often some balancing you have to do to make sure the GPU and CPU/mobo power are on different rails. Because you are using molex to 6 pin connectors, there is a chance that you are on the same rail as the CPU / motherboard power. This could definitely present itself as the problem you are experiencing (where the computer works fine some of the time and randomly shuts off when you ramp up the card for 3D due to the power draw).

 

[Puppies04]

The first thing I would look at would be your psu. There are 500w power supplies out there that would struggle to put out much more than half that number and even if yours is a "decent" brand, how old is it?

The very fact that you are having to convert molex connectors into 6 pin pcie connectors is ringing alarm bells in my head.

 

[martin.c.dean]

The previous card was an x1950 Pro - no problems with that whatsoever.

The computer was built in 2008 - so the psu is around 3 years old.

I'm not sure about the 12v rails, are these the wires coming from the psu? - how do I see if I have single or multiple?

There are several 4 pin connections coming off the main bulk of wires leaving the psu. One of these was connected to the previous card (x1950) - I'm using this one to run the new card (6950), plus another one, that was previously unused.

The 6950 comes with two cables that connect the 6 pins pcie slots in the card to two 4 pin wires coming out of the psu - the card is supposed to be powered in that way. Perhaps I'm using the term Molex incorrectly. I mean the 4 socket connections that come out of the power supply and plug into the various devices in the computer etc.

 

[MisterMac]

Check out your powersupply on the side.
note your Amps on the 12v rail.


99% your psu is one or both:

A. Old and slightly degraded
B. A very bad brand.


+ 6950 requires 550 W.


I wouldn't run a 6950 without "noname" 700W or a high quality 600 one.

 

[Spikesoldier]

unrelated, but you probably want to go to a 64bit OS because after adding the 2GB 6950, youve cut yourself down to 2GB usable system memory.

 

[martin.c.dean]

Ok the power supply says 'Model: LPK64'

I can't see a brand name.

I noticed that one of the 4 pin connectors has 8 wires running into it - this is the one that was powering the old card.

The other 4 pin has only 4 wires running into it. This was the spare connection, not powering anything. Branches from this run to the front fans in the computer.

Now if I connect the new card, the monitor won't even power up.

Old card works fine.

Can anyone recommend a good power supply that would let me run this card?

Is upgrading to a 64 bit system necessary, or can I leave this for now? How much of an issue is only having 2gb of system memory?

M

 

[Wuzup101]

Ok the power supply says 'Model: LPK64'

I can't see a brand name.

I noticed that one of the 4 pin connectors has 8 wires running into it - this is the one that was powering the old card.

The other 4 pin has only 4 wires running into it. This was the spare connection, not powering anything. Branches from this run to the front fans in the computer.

Now if I connect the new card, the monitor won't even power up.

Old card works fine.

Can anyone recommend a good power supply that would let me run this card?

Is upgrading to a 64 bit system necessary, or can I leave this for now? How much of an issue is only having 2gb of system memory?

M

I believe what Puppies was getting at was that almost all newer/modern power supplies have 6 or 6+2 pin connectors on them designed to power modern video cards. The fact that yours doesn't indicates that it's an older / low quality PSU.

From the info that we have, it's hard to even say that it's the power supply. It COULD be the card itself. If you have the funds, a PSU upgrade won't hurt. You probably would be able to get away with something in the 450-500 watt area with a single 6950 at stock clocks (even that might be higher than absolutely needed but it's never a problem having a bit too much). Buy a bit more if you can afford it (or a decent amount more if you plan to xfire in the future). There should be plenty of recommendations in the power supply forum... Note that the 1950 XT consumed far less power than the 6950 does... so the PSU does seem like it is the issue.

Note: in regards to the "multiple" rails topic, check out the sticker on your power supply where it shows the amperage of your 12V rail(s). You should see something like +12v (under DC output) and a number with an A after it (under max current). If there are multiple instances of +12V (IE: +12V1, +12V2, etc...) than you have more than one rail and it may be a balance issue.

 

[RavenSEAL]

You need a new power supply, period.

Take advantage of the fact that it's Black Friday.

 

[LoneNinja]

unrelated, but you probably want to go to a 64bit OS because after adding the 2GB 6950, youve cut yourself down to 2GB usable system memory.

That may very well be the cause.

OP, Skryim system requirements require 2GB ram, and recommends 4GB. A 32bit OS as yours can only recognize 4GB memory, some of that is needed for PCI I/O and other system resources, so you can't have a full 4GB of usable RAM. The 2GB Vram on your video card is included in that, so your system currently has less than 2GB of usable RAM. Then of your usable ram, anything running in the background plus Xp itself needs to use some of that, and Skryim may not have much RAM to work with.

Does the system crash playing any other games?

I don't know if this is the actual problem or not, but either way I would highly recommend upgrading to a 64bit OS.

 

[martin.c.dean]

Aha -

Ok so the game ran fine with the new card for 1-2 hours, and then crashed. Then it crashed everytime I tried to open it. But it ran fine at first.

I tried putting the card in again, installing drivers etc - now my computer starts up, but the monitor cuts out after 5 minutes, and I can hear the 6950 fans whirring hard.

To me that sounds most like a power issue, less a memory issue.

I have a feeling one of the molex I'm using isn't correct.

I'm going to try using a molex splitter from the 1 that powered my old card, then run 2x pci cables from it into the new card.

Failing that - I'll upgrade the power.

if that doesn't work, I'll return the card and get the 1gb version.

For power supplies, would the Corsair TX650 V2 do it?

Or should I spend the extra 30 quid and get the Corsair 850 watt?

 

[Wuzup101]

Aha -

Ok so the game ran fine with the new card for 1-2 hours, and then crashed. Then it crashed everytime I tried to open it. But it ran fine at first.

I tried putting the card in again, installing drivers etc - now my computer starts up, but the monitor cuts out after 5 minutes, and I can hear the 6950 fans whirring hard.

To me that sounds most like a power issue, less a memory issue.

I have a feeling one of the molex I'm using isn't correct.

I'm going to try using a molex splitter from the 1 that powered my old card, then run 2x pci cables from it into the new card.

Failing that - I'll upgrade the power.

if that doesn't work, I'll return the card and get the 1gb version.

For power supplies, would the Corsair TX650 V2 do it?

Or should I spend the extra 30 quid and get the Corsair 850 watt?

The 650 is more than enough for a single 6950. I'm running 2 of them in my system with a TX750 and the draw from the wall running furmark + prime 95 at the same time is ~650 watts (from a kill-A-wat). Get the 850 only if you want/need the headroom for a second/third card in the future (honestly buying a tad more than you need isn't a bad idea if you can afford it... but don't think that you need it).

 

[RavenSEAL]

Buy a new quality power supply 650w> and install a 64-bit version of windows 7, problems solved.

 

[martin.c.dean]

Ok so I just put in a corsair tx850.

I uninstalled old card, removed drivers, put in new card,
Start up computer. I started installing the drivers from the card manufacturers website - and halfway through the process the screen goes black.

I restart it, after waiting 10 mins - and just get a a black screen after the windows loading screen

What now?