Is the 8-pin necessary for i5-750? Can 4-pin handle it?

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10-18-2009, 10:59 AM
k0rben

Is the 8-pin necessary for i5-750? Can 4-pin handle it?

Hi guys, i have a question.
My post to i5 overclocking topic was little burried by posts with OC results, so i made a separated topic.

Its 8-pin (cpu power) necessary for a i5-750 cpu?

The situation :
cpu : i5-750
mobo: asus p7p55d
psu: arctic cooling fusion 550w

This psu has 2x 12v rails, each 17A, and only has 4-pin for cpu power.
The motherboard has 8-pin, but 4-pins are covered by black plastic "thing".
Is it safe to have combination mentioned above and only 4-pin plugged to motherboard for powering cpu?
Also, i found this
http://img113.imageshack.us/img113/663/steker.jpg

Are there any limitations when i only have a 4-pin? How about OCing? What is the pwr consumption of i5-750?

Can someone try runing on 4-pin instead of 8-pin? (im not responsible for any damaged hardware, personal injuries etc. :up: )

edit: oh i almost forgot! how about this 4to8-pin http://www.plinkusa.net/web4-to-8.htm ?

Thanks for your help!
10-18-2009, 12:46 PM
DAK1640

If the mobo has 8-pin, then use 8-pin. Simple as that. Anything else is a big comprimise, risk.
10-18-2009, 12:51 PM
k0rben

Err, thanks, but i think its like
p45 motherboard with 8-pin, socket 775,
and c2d vs. c2q.

c2q run without any problems on p45 mobo (8pin on mobo) with only 4-pin connected. I heard that there are only problems with overclocking, when the cpu has greater consumption.

c2d run w/out any problems with 4-pin or 8-pin.
10-18-2009, 06:51 PM
PlatoonSgtElias

Just use the 4pin, 8pin is just needed for some more stable overclocking, gets more power to the cpu. You wont gain anything when buying 4pin to 8pin connector, you would gain if you change your old PSU.
10-18-2009, 07:00 PM
dctokyo

use the 8-pin, it is there for a reason better safe then sorry.
10-18-2009, 07:05 PM
PlatoonSgtElias

Quote:

Originally Posted by dctokyo

use the 8-pin, it is there for a reason better safe then sorry.

lol, and how can he do that precisely?
The 8pin IS NOT NEEDED! But just is better for some overclocking because it can offer more power to the motherboard.
10-18-2009, 07:23 PM
dctokyo

Quote:

Originally Posted by PlatoonSgtElias

lol, and how can he do that precisely?
The 8pin IS NOT NEEDED! But just is better for some overclocking because it can offer more power to the motherboard.

I mean he should get a PSU that has 8 pins for the CPU, have you seen the latest EVGA boards? dual 8 pins these days.

also they sell 4 pin to 8 pin adapters,

Does the manual say that a 4 pin can be connected instead of 8 pin I wonder?

You can plug a 4 pin 12 volt power cable into an 8 pin EPS motherboard connector but there's no guarantee that it will work. If the motherboard expects only one 12 volt rail then a 4 pin 12 volt cable may work. If the motherboard expects two 12 volt rails (many dual CPU motherboards require one 12 volt rail per CPU) then it won't work. Even if the motherboard works with a 4 pin 12 volt cable, you are still only providing half of the current carrying capacity which would be provided by an 8 pin EPS cable. That can overheat both the motherboard connector and 4 pin cable. Scorched or melted connectors can be a result. A motherboard which has the 8 pin EPS connector expects a lot of current and you are taking a serious risk by plugging in a 4 pin cable. The 4 pin cable only fits at one end of the 8 pin EPS motherboard connector so you can't plug it in improperly. That is, it only fits into one end of the motherboard connector unless you force it. If the cable doesn't go into the socket easily then you're probably trying to plug it into the wrong end. But then again, it's not a good idea to try to run with a 4 pin cable in an 8 pin motherboard anyway.
10-18-2009, 07:32 PM
urgrandpasdog

Quote:

Originally Posted by dctokyo

[FONT="Comic Sans MS"]

also they sell 4 pin to 8 pin adapters,

The 4-pin to 8-pin won't really do a whole lot to help in this situation. The 8 pin is just 2x 4 pin cables in parallel to allow a greater amount of current to be delivered to the board.
10-18-2009, 07:44 PM
dctokyo

Quote:

Originally Posted by urgrandpasdog

The 4-pin to 8-pin won't really do a whole lot to help in this situation. The 8 pin is just 2x 4 pin cables in parallel to allow a greater amount of current to be delivered to the board.

I agree,I forgot many companys do not support adapters for their main boards but if he only has a 4 pin PSU then he does not have much of a choice, I still feel it would be better to get a new PSU that has a 8 PIN for the CPU. Basically the more power rails that go in, the less resistance on each line.

So its more efficient to use 8 pins not 4, but 4 will still work with less efficiency.
10-18-2009, 10:24 PM
fallwind

I have 4 i7's running at 4GHz on UD3R's powered by a 4 pin and they are fine. I know if you push the vcore or OC too high you can start to melt the plug or the board though so be careful.
10-19-2009, 01:38 AM
Zeus

All my last mobo's (Asus) had 4 out of 8 pins covered with a small lid, meaning 4 will do but 8 is better.

Did your board come with such a lid?
10-19-2009, 02:44 AM
elpibe10

4-pin is perfectly fine as long as you're not going to do some extreme overclocking involving massive Vcore adjustments.

I've been using my Asus P7P55D with i7-860 (stock speed) and an FSP Zen 400W fanless psu (which has only the 4-pin cable) for quite a while now and it is 100% stable.
10-19-2009, 02:55 AM
LuckyNV

Quote:

Originally Posted by Zeus

All my last mobo's (Asus) had 4 out of 8 pins covered with a small lid, meaning 4 will do but 8 is better.

Did your board come with such a lid?

The lid is there to prevent dopey users trying to force the 4 pin plug in the wrong way.
10-19-2009, 05:19 AM
k0rben

fallwind & elpibe10, thanks, thats what i need to hear.
Im not going to do EXTREME OC of the i5-750, i just want to enable turboboost, and maybe leave it on stock freq.
Thanks for all replies.
and yes zeus, i have a small black lid on 8-pin, covering 4 of the pins.
10-19-2009, 05:35 AM
elpibe10

Quote:

Originally Posted by k0rben

fallwind & elpibe10, thanks, thats what i need to hear.
Im not going to EXTREME OC of the i5-750, i just want to enable turboboost, and maybe leave it on stock freq.
Thanks for all replies.
and yes zeus, i have a small black lid on 8-pin, covering 4 of the pins.

I left mine with Turboboost enabled too.

The black lid covering the other 4-pin is there for a reason. It's an indication that it'll work (just as well) with just 4-pin connected.

BTW, I've done the same with my previous Q9450 (running @ QX9770) + Asus P5K Deluxe too.
10-19-2009, 05:47 AM
k0rben

elpibe, do you notice any signs of system unstability? isnt the 4-pin cable, plug etc. overheating?
10-19-2009, 06:20 AM
elpibe10

Quote:

Originally Posted by k0rben

elpibe, do you notice any signs of system unstability? isnt the 4-pin cable, plug etc. overheating?

It's totally stable.

No abnormal temps in the system (everything's in the 30+ deg C range) despite running on really low-speed fans and fanless PSU + ATI 4670.

You can view my rig here (look for 'BLACK BEAUTY' - name of that particular rig) :

http://www.freewebs.com/elpibe10/
10-19-2009, 06:37 AM
dctokyo

Quote:

Originally Posted by k0rben

elpibe, do you notice any signs of system unstability? isnt the 4-pin cable, plug etc. overheating?

Have you read the manual?

go to page 3-28 and read about the PSU requirements for this board.
10-19-2009, 09:24 AM
k0rben

Its on 2-38, and this is it :
http://img340.imageshack.us/img340/3972/sggswa.jpg
Well it says, use ATX 2.0 or higher (& minumum power of 600w what i think is crap)
The mentioned PSU is 2.2...
http://www.arctic-cooling.com/catalo...th=38_&mID=238

it also says dont forget to plug your 8-pin. But if my psu dont have 8-pin, i will use 4-pin huh? As elpibe said, that the plastic lid is there for some reason. (but not because of dopey users imo)

then i dont understand what is this for :shakes: ...
http://www.plinkusa.net/web4-to-8.htm
for a better feeling? lol.
10-19-2009, 04:03 PM
elpibe10

Quote:

Originally Posted by k0rben

Its on 2-38, and this is it :
Well it says, use ATX 2.0 or higher (& minumum power of 600w what i think is crap)
The mentioned PSU is 2.2...
http://www.arctic-cooling.com/catalo...th=38_&mID=238

it also says dont forget to plug your 8-pin. But if my psu dont have 8-pin, i will use 4-pin huh? As elpibe said, that the plastic lid is there for some reason. (but not because of dopey users imo)

then i dont understand what is this for :shakes: ...
http://www.plinkusa.net/web4-to-8.htm
for a better feeling? lol.

Don't bother reading the manual. They seem to just duplicate the text for every model of mainboard. :yepp:

Trust me. 4-pin definitely works w/o any glitch as long as you're not into extreme overclocking (eg. pushing your i5-750 beyond 4GHz). :up:
10-19-2009, 04:06 PM
Neuromancer

Quote:

Originally Posted by dctokyo

I mean he should get a PSU that has 8 pins for the CPU, have you seen the latest EVGA boards? dual 8 pins these days.

Marketing schtick, or maybe they did not know about the i7 cold bugs and thought at 7+ GHz it would need an additional 400 Watts of power :shrug:
10-19-2009, 04:44 PM
autobot

Rule of thumb, if the motherboard comes with a little black tab covering 4 of the pins, then a 4-pin power connection will work fine for most users.
10-19-2009, 05:49 PM
Hsusy

When I was working with a PC retail shop, putting out base spec PCs that the user is never even going to touch the BIOS let alone OC, little black tab or not, 99% of the PCs went out with 4 pins connected because the stock PSU that comes with the case will only come with 4 pin connector. I don't recall any PC ever have a problem and we went through quite a few mainboards with 8 pin connectors with no black tabs. I personally would have eight pin coonectors for my own PCs, not a techinal decision, just more for the point of peace of mind.
10-20-2009, 02:22 AM
DAK1640

Will it work yes, but not the smart thing to do.:up:
10-20-2009, 03:30 AM
dctokyo

Quote:

Originally Posted by DAK1640

Will it work yes, but not the smart thing to do.:up:

+1 :up:
10-20-2009, 04:13 AM
chuck4456

12V is 12V be it from a 4 pin or 8 pin connector.
FWIW the 8 pin power connector was originally designed for more efficient power delivery for dual CPU servers. It had nothing to do with overclocking. The design evolved over to mainstream desktop boards for that efficiency as well as reduced production costs.
I'd be more worried about two 17A rails.
If you plug any kind of power hungry video card into that system, it's going to fall flat on its face.
Everybody worries about WATTS yet never consider AMPS.
10-20-2009, 04:24 AM
k0rben

I always care about amps, im not going in dual hd4890 or something "very hungry" :)
imo 2x 17A would be fine.
11-05-2009, 10:36 AM
k0rben

Got another one :
This is Asus P7P55D LX
http://www.asus.com/product.aspx?P_I...84O&templete=2
http://www.asus.com/websites/Global/...8cwXXh_500.jpg
P55 (1156) mobo and it has only 4-pin pwr.
But maybe i'll take Corsair TX650 :) and won't change psu at least 4 yrs.