Cards needing 8 pin PCI-E power??

[MU51CL]

I'm not much of a gamer - not really interested in shooting stuff...:smile:

But I do like my motorsport and I play GTR2 a little bit. At some point there should be GTR3 in DX10. For the moment I get by just fine with a 8600GT 512 @ 1680x1050 on a 22"WS. I will need a lot more graphics power for GTR3.

As I am upgrading my PSU now, the big question is, do I need to factor in the potential need for a card with a PCI-E 8 pin power connector? I mean, what sort of card needs it? There seems some quite powerful cards using 6 pin, and those like 2900XT / 3870X2 have both....

Thoughts guys?

[Schwarz]

If you are going for a nvidia type of card you will only need 6 pinners.
On the other hand ATI uses the 8 pin but usualy those cards come with an adapter.
2x4pin Molex to 8 pinner.
Some PSUs may come with the 8 pin though, would be a good thing to check.

[Scott]

I would get one that offers 8pin and 6pin on the PCI-E. Believe me 8pin is coming to all cards.

[Schwarz]

Well mostly all new PSUs offer that so if you are getting a new PSU still check that it has them but like I said most new PSUs have hem.

[MU51CL]

Thanks guys.
It is reasonably common to have 2 x 6 pin on PSU's but 8 pin is more rare until you get into more expensive (& larger, more powerful ones than I really need).
I want to get something decent that will be a bit of an investment through a couple of upgrades, so it seems a good idea to cover all the bases.
So far the Zalman HP-600 looks a good choice.

[Kougar]

I might suggest the Corsair VX550... cheapest one on Newegg with one 8-pin PCie connector + one 6-pin PCIe connector, and more important than the low price they make some very good power supplies. http://www.newegg.com/Product/Product.aspx?Item=N82E16817139004

[PP Mguire]

but 8 pin is more rare until you get into more expensive (& larger, more powerful ones than I really need). My Ultra X2 550watt is getting old and it has an 8pin. It just all depends on the PSU.

[MU51CL]

Thanks for the heads-up Kougar.
Interesting things about VX550 - I see on their site that it has 6 pin and 8 pin. However the pdf manual and a review I'd seen (at HardOCP, linked from Corsair site) call it as 2 x 6 pin ??
Also that it is significantly cheaper than the modular HX520 in the States. Here (Australia) they sell for the same price.
So here we pay too much for VX550 which rubs me up the wrong way, just on principle.

Another PSU about the same configuration ( 1x6 pin, 1x8 pin) is the Seasonic S12II 500, but they are very scarce here. The 430 watt is everywhere though....

Coolermaster's M520 has an 8 pin, but hard to find a thorough review on one. Same price here as VX550.

It's "just" a PSU, so many to choose from, and still manages to be "difficult" :)

[darkorb]

430 would be a little low for youre system.

500-600watt would be the sweet spot. Dedicated 8pin is better than 2xmolex adapter it comes with

[PP Mguire]

Best bet, stick with an Nvidia card and you wont need an 8pin.

[Methious]

Aren't some motherboards coming out with 8 pin to power the cpu now? I know the Ultra 700w I just got has 2 6pin pcie, one 8 pin split for cpu (had to call Ultra to make sure I wasn't going to fry my board).
There's no 8 pin pcie on mine so if I go ATI looks like an adapter for me.

[srpeters18]

Most all new mobo's use 8 pin to the CPU.

[Ranzear]

My Tagan 1100w has four six-pins and one eight-pin.

Nvidia just used two Six-pin connectors on the 88 Ultras. Same difference, theres two cables ziptied together to my 8-pin connector anyway though it is a bit burlier too. I'm now trying to find the female for it so I can run my peltier from it.

The 8-pin CPU power came about with the quad Xeons I think. Server stuff migrating over again I guess.

[PP Mguire]

What does the 8pin and 4pin do on the motherboard? I never figured that one out.

[srpeters18]

That's where your CPU power comes from.

[Miker]

8Pin is extra CPU power, 4Pin Molex is for PCI-e power as the old standard 24 pin doesn't always have enough juice. That 20-24 pin has been around for a long time.

[srpeters18]

I assumed he was talking about 4/8 pin for the cpu power and not knowing what it was. The 780i doesn't even have the 4 pin molex and requires an 8 pin, not like the 680i where you could still use the 4 pin if that's all you had.

[Miker]

I assumed he was talking about 4/8 pin for the cpu power and not knowing what it was. The 780i doesn't even have the 4 pin molex and requires an 8 pin, not like the 680i where you could still use the 4 pin if that's all you had.

So the 8Pin is CPU and PCI-e power?

[srpeters18]

Nope, the PCI-e on the card is enough. The molex was designed for older cards that didn't have onboard power plugs.

[Ranzear]

Further clarification would be the difference in the Xeon 8-pin CPU power connector and the 8-pin PCIe connector. I'm not immediately sure if they are the same...

Did find this image
http://lib.store.yahoo.net/lib/directron/p4atx65f01.jpg
Where that 4+4 connector makes the 8-pin power for the newer Xeons or uses just one for the CPU power plug that came about with the Pentium 4.

AFAIK this is different from the one-piece single tabbed and likely differently keyed 8-pin PCIe connector. Though if its the same I'm going to flip out a bit because I've been trying to find the female PCIe for a month now.

[srpeters18]

Just went looking at some pictures, the 8-pin CPU and 8-pin PCIe are keyed differently, won't work interchangeably.

[MU51CL]

Yes indeed. The 8 pin PCI-e and CPU 8 pin are different keys and not interchangeable.
This had me head-scratching on the Zalman HP-600 PSU.
There is an 8 pin modular connection on the case that originally had 2 different cables for it. It was marked "CPU2 / PCI-e" and had an 8 pin CPU connector on one cable that attached there, and a 8 pin PCI-e connector on a different cable that could attach there.
Now it SEEMS that the connection is marked simply PCI-e and the cable is just one and is a 6+2, only for GOU use - ie doesn't support a second CPU anymore. Not that is of any use to me anyway......

Anyhow, I note that the Corsair HX520 now comes with 2 x 6+2 pin PCI-e as an "upgrade" or so said a review I read. But nothing on that subject from Corsair themselves, either on their site or in the manual you can download.

Is there anyone with a HX520 that has this set-up and confirm?

[PP Mguire]

Well i was strictly talking about the 4pin and 8pin for the CPU. I dont think the 4pin is for CPU cause i can use my machines without it plugged in.

[srpeters18]

I don't know. Maybe its dependent on mobo/cpu? Because in the manual for the 680i and 780i it says it needs them for CPU power. I think I read somewhere today that it started with P4.

[bromro]

I've read in a bunch of reviews of the 3870 X2 that you can put two 6 pins instead of one 6 and one 8, and all that will happen is the overclocking functions will be disabled.

[PP Mguire]

Maybe its with just Intel then. Cause none of my AMD machines have needed it.

[srpeters18]

Yeah, pretty sure its Intel only. None of my AMD machines use it either.

[PP Mguire]

Well they have it, i just think it is required to be plugged in to work.

[Kougar]

To clear things up.

CPU uses either a 4pin AUX connector or a 8pin EPS 12v connector (which is nothing more than two 4pin AUX connectors combined).

PCIe normally uses a 6pin connector. R600 and R680 both introduced the 6+2pin (8pin) PCIe connector.

Just went looking at some pictures, the 8-pin CPU and 8-pin PCIe are keyed differently, won't work interchangeably.

If a user somehow managed to cross a EPS 12V connector with a 6+2pin PCIe connector, there would be fireworks. They will also be lots of dead hardware after the smoke clears... this is why they are keyed differently.

I've read in a bunch of reviews of the 3870 X2 that you can put two 6 pins instead of one 6 and one 8, and all that will happen is the overclocking functions will be disabled.

I was not aware of this, but this is what was done for the original R600 so it sounds like it is likely true.

[Sadasius]

I was not aware of this, but this is what was done for the original R600 so it sounds like it is likely true.

Yeah it's true. Checked all the wiring and keys. Two 6 pin PCie power plugs will work on the 3870X2. The 8 pin just adds two extra grounds on the end and the power of the 6 pin is exactly the same as the 8 pin. I guess for heavy overclocking they want to make sure you are really grounded hence why the overclocking is disabled if you use a 6 pin instead of an 8 pin. But technically you can cheat through this by adding two extra grounds and hook them to the grounds on the 6 pin and it should work and will get overclocking functions as well.

[bromro]

But technically you can cheat through this by adding two extra grounds and hook them to the grounds on the 6 pin and it should work and will get overclocking functions as well.

Would anything bad happen to the card if you add two extra grounds from the six pin?

[Kougar]

Yeah it's true. Checked all the wiring and keys. Two 6 pin PCie power plugs will work on the 3870X2. The 8 pin just adds two extra grounds on the end and the power of the 6 pin is exactly the same as the 8 pin. I guess for heavy overclocking they want to make sure you are really grounded hence why the overclocking is disabled if you use a 6 pin instead of an 8 pin. But technically you can cheat through this by adding two extra grounds and hook them to the grounds on the 6 pin and it should work and will get overclocking functions as well.

Okay, you got me on this one. I was sure that it was a 12v+ground pin, but after a good deal of googling you are correct. For whatever strange reason they are both ground pins... so in effect a HD 3870 X2 has 6 12volt pins and 8 grounding pins. I have no idea why they'd need the extra ground pins when they already have a grounding pin for every 12v pin.

[Sadasius]

I think it has to do with wire size when it comes to wattage. I asked a technician why this would be so and he told me the only reason would be that the wires would be running under maximum load and needed another two grounds to help with the load circuit. He said it is a possibility that it can cause a fire if there was a wire that was overloaded with wattage. So it needs all the separate grounds. So my idea of attaching the grounds to the 6 pin grounds may not be a good idea after all. He said you could do it but would have to watch the wires under load and see if they are hot from all the wattage going through them. If they are cool then no worries. But if they are hot then disconnect them immediately.

[Ranzear]

Or they're for extra grounding of the 12v power coming from the motherboard, rated 75w, which might not have an effective ground path back through the mobo.

[PP Mguire]

Ok well the video card cabling is making sense to me. But i still dont uderstand about the 8 and 4 pin for the CPU. Im off tomorrow ill just Google around.