8 pin PCI-e Cables

byron_hinson · 25 Jun 2007 at 08:29

Anyone know if these are out to buy anywhere at all, my PSU supports it but didn't come with the cable which is a pain.

Tute · 25 Jun 2007 at 08:32

OcUK don't appear to, so anywhere suggested would be a competitor.

Can I just ask - is this for the Radeon 2900XT? As 2x6pin connectors will work with this card.

byron_hinson · 25 Jun 2007 at 08:33

Not for overclocking they won't!

paradigm · 25 Jun 2007 at 08:53

byron_hinson said:
Not for overclocking they won't!

Incorrect. Overclocking with CCC Overdrive needs the 8-pin, overclocking with anything else (AMDGPUClockTool, ATITool, etc) you are fine on the 2 x 6-pin connectors.

Anyway, even if you wanted to use CCC overdrive, you could always connect the last two pins yourself. They both go to ground, and you can use an old PSU's ATX-12v (4-pin) connector cut in half to acheive the correct plug

Dead simple to do, acheives the same results

Tute · 25 Jun 2007 at 08:56

I was just looking on Google for some information about overclocking with 2x6 pin connectors, I knew it was possible but wanted some evidence to back it up!

Hang on though, if they both go to ground, then why does anyone need to bother with this new 8 pin connector? What was wrong with the old 6-pin one? :confused:

getcarter · 25 Jun 2007 at 09:06

to make you go out and buy a brand new shiny PSU of course

paradigm · 25 Jun 2007 at 09:34

Tute said:
Hang on though, if they both go to ground, then why does anyone need to bother with this new 8 pin connector? What was wrong with the old 6-pin one?

In the actual specification IIRC one of the two additional pins is a voltage sense or something similar. Drawing it to ground gives a reading that allows CCC overdrive to run. So whilst the actual specification of the new PCIe 8-Pin connector does add a new feature, its superfluous.

Tute · 25 Jun 2007 at 10:33

paradigm said:
In the actual specification IIRC one of the two additional pins is a voltage sense or something similar. Drawing it to ground gives a reading that allows CCC overdrive to run. So whilst the actual specification of the new PCIe 8-Pin connector does add a new feature, its superfluous.

So what were they thinking when they designed this new connector? "Lets be as difficult as possible"?

If the 8-pin connector isn't supplying any more power than the 6-pin one does, what on earth was all the fuss about? :confused:

Teaf · 25 Jun 2007 at 11:25

Tute said:
So what were they thinking when they designed this new connector? "Lets be as difficult as possible"?

It's something to do with the power the board can suck out when under strain (ie. largely overclocked) and apparantly it has a chance (very low, but a chance nevertheless) of melting the wire or causing damage to the card or the wire if the extra connectors aren't used. From reading up on it, people are saying that it's 2 extra ground's, but other places are saying that it's 1x 12vDC and 1x ground, because the wire has 4x yellow cables and 4x black which indicates another 12vDC, instead fo 3 yellow and 5 black which would mean 2 ground.

Tute · 25 Jun 2007 at 11:40

flibby said:
It's something to do with the power the board can suck out when under strain (ie. largely overclocked) and apparantly it has a chance (very low, but a chance nevertheless) of melting the wire or causing damage to the card or the wire if the extra connectors aren't used. From reading up on it, people are saying that it's 2 extra ground's, but other places are saying that it's 1x 12vDC and 1x ground, because the wire has 4x yellow cables and 4x black which indicates another 12vDC, instead fo 3 yellow and 5 black which would mean 2 ground.

Well I could understand if the 8-pin provided another 12VDC connection.

ChrisD. · 25 Jun 2007 at 11:43

Are the new NVIDIA cards 8 pin? If not I recently spend about 120 quid on a PSU that I'll have to replace

LoadsaMoney · 25 Jun 2007 at 11:46

You don't need the 8x pin to overclock the 2900, you can overclock it fine with just 2x 6 pins connected, all the 8x pin does is allow you to use the overdrive of the CCC, but just connect 2x 6 pins and use ATi Tool.

Theres no reason to get the 8x pin for the 2900 at all, unless you want the overdrive section of the CCC to show up.

chaparral · 25 Jun 2007 at 12:28

byron_hinson said:
Anyone know if these are out to buy anywhere at all, my PSU supports it but didn't come with the cable which is a pain.

Which PSU do you have ???

and why did it not come with the 8 pin PCI Express cable if it supports it ?? :confused:

Teaf · 25 Jun 2007 at 12:29

It's probably for nice compability with PCI-E 2.0 as well. Whilst the card isn't PCI-E 2.0 spec, you will probably be able to just use the 8-pin connector and nothing else when you use the card on a PCI-E 2.0 board. Because the card draws a maximum of 300w currently, it needs 2 connectors on PCI-E 1.1 boards. Ie. 75w from the slot, 75w from the 6 pin connector and 150w from the 8 pin connector. But since PCI-E can suck 150w straight from the board slot instead of only 75w, then you only need an additional 150w for supply the maximum power need to the board, which is just 1x 8 pin connector.

paradigm · 25 Jun 2007 at 12:31

LoadsaMoney said:
You don't need the 8x pin to overclock the 2900, you can overclock it fine with just 2x 6 pins connected, all the 8x pin does is allow you to use the overdrive of the CCC, but just connect 2x 6 pins and use ATi Tool.

Theres no reason to get the 8x pin for the 2900 at all, unless you want the overdrive section of the CCC to show up.

Do you ever read a thread you post in? This has already been covered once.

Besides, ATITool is not a great way of overclocking at the moment, especially in vista, it messes with voltage/fan profiles when changing clock speeds, and as far as I can tell doesn't even always set clocks correctly.

AMDGPUClockTool is the best option by far for the HD2900XT at the moment, CCC:OD doesn't go high enough (900MHz RAM limit

).

helmutcheese · 25 Jun 2007 at 12:41

Small paperclip mod gets you full Overdrive with only 6pins.

MilanoChris said:
Are the new NVIDIA cards 8 pin? If not I recently spend about 120 quid on a PSU that I'll have to replace

Not yet my Superclocked 8800Ultra is 2x 6pins.

LoadsaMoney · 25 Jun 2007 at 12:54

paradigm said:
Do you ever read a thread you post in? This has already been covered once.

I know, but its better to have more than one person confirming it.

ChrisD. · 25 Jun 2007 at 13:24

helmutcheese said:
Not yet my Superclocked 8800Ultra is 2x 6pins.

Thanks for the clarification. I could run two of them then

Oooh if I had the cash for one yet alone two and a monitor to make the cards actually do some hard work :rolleyes:

jaykay · 25 Jun 2007 at 13:26

MilanoChris said:
Thanks for the clarification. I could run two of them then

Oooh if I had the cash for one yet alone two and a monitor to make the cards actually do some hard work

Dont get the ultra they cost way too much for what they are. Plus the newest GTX have the same core so it will clock the same.

ChrisD. · 25 Jun 2007 at 13:29

I know mate, I'm dreaming. My 7900 GTX 512 is happily chugging away and doing what I want it too for the time being so an upgrade is of the cards till I notice it slowing down.

Plus I'm in a RMA debate about my second 7900 which bit the dust, so depending on the comeback from that I'm hoping for a 7950GX2 or 8800GTS 320.