Two PSUs - Irregular Setup

[unr3al]

Okay guys I hope this isn't an insanely stupid question. I really need an improvement, so I'm desperate. I haven't posted here in forever, but it feels really good to be back.

To start off, I have two GPUs, a Radeon HD4670 512MB and a Radeon HD4850 1GB. My current CPU is an Intel Core2Quad Q8200; the 95W chip. And with that, I am using the Radeon HD4670. Crazy, right? I know.

Now, in the past I used the Radeon HD4850 together with a 65W AMD Athlon X2 250 and it worked fine, at least until I tried overclocking anything. You see, the HD4850 (a POS design by Force3D, NEVER buying from them again) has no external power connector. Yes, you read that right, what used to be a high-end card, with no 6-pin connector. It draws all its power from the PCIe x16 slot.

This brings me to the problem, why my CPU/GPU ratio is so ridiculously off (I'm a gamer for crying out loud!). Because the quad draws 95W, the HD4850 simply doesn't want to play nice. Artifacts all over and eventually BSOD, or worse, just a reboot. It just doesn't get enough power. The card is currently being used in another system that once again has a low power AMD CPU and not one single issue, so juice is definitely the problem.

A friend of mine suggested this, but I thought I would ask here first before going through all the trouble of actually attempting it since it's such a hassle. What I have in mind, is to connect two PSUs, my current 550W box to power the motherboard, graphics card, HDDs, optic drives and perepherals, with a 300W unit to solely power the CPU via the 4-pin connector.

My question now obviously is, will this even work? Not in the sense of will my PC run, because that I already know. But will having it setup like this make a difference as to whether I can run that damn HD4850 alongside the quad? You can imagine I don't really want to mess around with PSU power cables and such nonsense if it won't even make a difference...

If this makes sense, I would be pretty elated. Having to run most of my games at medium to low quality really brings me down, not to mention some games like GTA4 that I can't run at all!

 

[MrTeal]

Okay guys I hope this isn't an insanely stupid question. I really need an improvement, so I'm desperate. I haven't posted here in forever, but it feels really good to be back.

To start off, I have two GPUs, a Radeon HD4670 512MB and a Radeon HD4850 1GB. My current CPU is an Intel Core2Quad Q8200; the 95W chip. And with that, I am using the Radeon HD4670. Crazy, right? I know.

Now, in the past I used the Radeon HD4850 together with a 65W AMD Athlon X2 250 and it worked fine, at least until I tried overclocking anything. You see, the HD4850 (a POS design by Force3D, NEVER buying from them again) has no external power connector. Yes, you read that right, what used to be a high-end card, with no 6-pin connector. It draws all its power from the PCIe x16 slot.

This brings me to the problem, why my CPU/GPU ratio is so ridiculously off (I'm a gamer for crying out loud!). Because the quad draws 95W, the HD4850 simply doesn't want to play nice. Artifacts all over and eventually BSOD, or worse, just a reboot. It just doesn't get enough power. The card is currently being used in another system that once again has a low power AMD CPU and not one single issue, so juice is definitely the problem.

A friend of mine suggested this, but I thought I would ask here first before going through all the trouble of actually attempting it since it's such a hassle. What I have in mind, is to connect two PSUs, my current 550W box to power the motherboard, graphics card, HDDs, optic drives and perepherals, with a 300W unit to solely power the CPU via the 4-pin connector.

My question now obviously is, will this even work? Not in the sense of will my PC run, because that I already know. But will having it setup like this make a difference as to whether I can run that damn HD4850 alongside the quad? You can imagine I don't really want to mess around with PSU power cables and such nonsense if it won't even make a difference...

If this makes sense, I would be pretty elated. Having to run most of my games at medium to low quality really brings me down, not to mention some games like GTA4 that I can't run at all!

What kind of 550W PSU is it?

From what you describe, it doesn't sound like it's a PSU problem, but a cabling one. The CPU draws its power from the 4 pin CPU connector, while the motherboard and all the PCIe cards draw power from the 24pin ATX connector which only has two 12V wires for all that.

The difference with the card running in the X4 system could just be related to the motherboard itself and how much power it consumes or how much it can deliver to the PCIe slot. You could try a powered PCIe riser cable to see if that helps the issue, but I honestly wouldn't want to spend $10 on that when you could probably pick up a used 5770 or 5850 for only a little more money.

 

[unr3al]

The 550W is a Huntkey. Yes I know POS and all that, but I've had it going strong for about 5 years now. The 300W is a Gigabyte. So I tried the dual PSU setup, didn't make one iota of a difference. Whole PC locks up during the first 3DMark 2003 bench. I looked at the PCIe riser cables you mentioned and it definitely looks like that might actually be a solution, but as you said, I might as well get a 5770 or something similar. Especially if I could trade the 4670. Ah well, back to playing Skyrim on med-low settings. Thanks for the input!

 

[HOOfan 1]

A lot of low end power supplies do not do well when you use only the 12V from them, which you would be doing if you only powered the CPU with one

 

[unr3al]

Ancient post. But I saw it just now and thought I should post an update. The problem was sorted when I got a GTX460 that has the two 6-pin power connectors the HD4850 didn't have. Now everything runs as it should, without changing my PSU or CPU.