Underclocking & undervolting an i7 920

[dorfma05]

Hello all. I was looking to put together a low power home server. I have a core i7 920 machine I was thinking of using for this purpose.

Is underclocking the processor a viable option to reduce power consumption? If so, to what degree can you reduce it before things stop working?

I'd imagine a drastically underclocked 920 @ say 1ghz would be more than enough for a home sever, especially with 8 threads.

Has anyone tried this? I believe that there was a square relationship between power an voltage on a CPU, iirc.

There may be cheaper options but I already have this machine so it is essentially free for me to do this.

Thanks all in advance.

 

[Magic Carpet]

My 950 is only responsible for encoding videos. This platform is just way too power hungry (when compared to SB/IB), even when the lowest P-state is enforced. If you want to save power, choose something else.

 

[Makaveli]

My 950 is only responsible for encoding videos. This platform is just way too power hungry (when compared to SB/IB), even when the lowest P-state is enforced. If you want to save power, choose something else.

Agreed the x58 chipset alone uses quite abit of power.

You may be better off just getting rid of it and going sb/Ib

 

[OILFIELDTRASH]

I had a i7 930 I was using for a htpc. I didn't need much CPU power so I tried undervolting and also lowering clockspeeds to save power. I used a kill a watt for measurement. It really didn't help much if at all. I'm talking a few Watts. I finally just sold it. Its a great platform if you are only going to use it for short periods of time. But something that needs to be on a lot I'd go a different direction.

 

[blckgrffn]

Considering that the platform has held its value pretty well (arguably, still superior to any AMD choice if games are your deciding factor) now might be a good time to sell it and pick up a i3 or something unless you really need some grunt.

 

[Makaveli]

Its not just games Nehalem > Bulldozer in many apps aswell.

 

[Ferzerp]

Its not just games Nehalem > Bulldozer in many apps aswell.

And it came out in 2008.

 

[dorfma05]

Thanks everyone for the input.

Instead of underclocking the i7 920 for the server, maybe I'll build a new home server on the cheap. For simple media streaming, audiogalaxy server, etc. will one of those Mini ITX Atom boards work well? Anything CPU intensive I could do on my i7 920 machine still. I'm basically looking to do a little more than what a NAS device does. (Plus, I'd like to play with WHS 2011.)

 

[ShintaiDK]

I would forget Atoms. Stay MiniITX ofcourse, but get an SB lowend chip and use the IGP. They are down to 50$ or so for the CPU and 50$ for a MiniITX board. Then you can also play movies and stuff that aint supported by the HW decoder. And its basicly gonna use the same power.

 

[tigersty1e]

Idle power consumption is not as bad as everyone makes it out to be.

Lowest idle stock with my 920 was at 118 watts.

Take my same system and add in a 3750k, samsung 30nm ram 1.35 v, gigabyte z77 ud3h and idle is 88 watts stock bios settings.

30 watt idle difference between ivy bridge and bloomfield. Bloomfield becomes power hungry once ovreclocked and run up to 21 multi.

I probably could get the 30 watt difference 5-15 watts lower with some lower bclk and watts, and using the samsung 30nm ram.

The best part is that heat is almost non-existant once underclocked.

http://www.anandtech.com/bench/Product/47?vs=551

You want to look at the second to last chart because your cpu should be kept locked at 12 multi for low usage stuff. Very close.

 

[dorfma05]

How's this look?

Foxconn H61S LGA 1155 Intel H61 Mini ITX Intel Motherboard - http://www.newegg.com/Product/Produc...82E16813186216

Intel Celeron G530 Sandy Bridge 2.4GHz LGA 1155 65W Dual-Core Desktop Processor Intel HD Graphics BX80623G530 -
http://www.newegg.com/Product/Produc...82E16819116409

Kingston 4GB 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) Desktop Memory Model KVR1333D3N9/4G -
http://www.newegg.com/Product/Produc...ddr%203%201333

I have a bunch of 2TB WD Green Drives I'd use with this. Can anyone recommend a good case that will support 6 or more 3.5" drives? The only one I can find thus far is the Array R2 but that's more expensive than the mobo/cpu/proc. Anyone do this on the cheap?

 

[tigersty1e]

just use your 920, lock multi to 12, turn off ht and idle power consumption is very close to idle power consumption to the sb system.

power consumption between the 2 systems starts to show once loaded up.

 

[ShintaiDK]

How's this look?

Foxconn H61S LGA 1155 Intel H61 Mini ITX Intel Motherboard - http://www.newegg.com/Product/Produc...82E16813186216

Intel Celeron G530 Sandy Bridge 2.4GHz LGA 1155 65W Dual-Core Desktop Processor Intel HD Graphics BX80623G530 -
http://www.newegg.com/Product/Produc...82E16819116409

Kingston 4GB 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) Desktop Memory Model KVR1333D3N9/4G -
http://www.newegg.com/Product/Produc...ddr%203%201333

I have a bunch of 2TB WD Green Drives I'd use with this. Can anyone recommend a good case that will support 6 or more 3.5" drives? The only one I can find thus far is the Array R2 but that's more expensive than the mobo/cpu/proc. Anyone do this on the cheap?

Looks fine.

6 HDs will kill idle power, unless they spin down. Unfortunately I only know those chassis with 1-2 3½" bays and 1-2" 2½" bays.

My HTPC is a SG08B with an old G1 80GB SSD and a 1½TB green HD.

My gaming rig btw idles in the 40-50W area. (See sig.)

 

[Ferzerp]

Corsair 600T will support 6 drives, 9 if you bought another 3 drive bay, as it has room for a 3rd, but it's not cheap (or small)

 

[Magic Carpet]

Can anyone recommend a good case that will support 6 or more 3.5" drives? The only one I can find thus far is the Array R2 but that's more expensive than the mobo/cpu/proc. Anyone do this on the cheap?

This can equip 7 of them. Tool-less design. Pretty good for the price. Also, I would rather get an mATX board with more sata ports, if this is going to be a file server, more ports will come in handy.

 

[coffeejunkee]

Idle power consumption is not as bad as everyone makes it out to be.

Lowest idle stock with my 920 was at 118 watts.

Take my same system and add in a 3750k, samsung 30nm ram 1.35 v, gigabyte z77 ud3h and idle is 88 watts stock bios settings.

30 watt idle difference between ivy bridge and bloomfield. Bloomfield becomes power hungry once ovreclocked and run up to 21 multi.

I probably could get the 30 watt difference 5-15 watts lower with some lower bclk and watts, and using the samsung 30nm ram.

The best part is that heat is almost non-existant once underclocked.

http://www.anandtech.com/bench/Product/47?vs=551

You want to look at the second to last chart because your cpu should be kept locked at 12 multi for low usage stuff. Very close.

Personally I think 30W is quite significant, but look what happens to idle power when you remove the vidcard and use the igp.

dorfma05, don't forget Array comes with 300W psu.

 

[bleucharm28]

get a 1366 Xeon chip? if your board support it. some of those chips are low 80's

 

[tigersty1e]

Personally I think 30W is quite significant, but look what happens to idle power when you remove the vidcard and use the igp.

dorfma05, don't forget Array comes with 300W psu.

30w is big, but my 920 was with 1.6v 1600 ram and a high-end motherboard versus a stock 3750k with 1.35 samsung ram and lower-end mobo.

better go off anand's numbers, which show 7w difference. add another 8 watts for a 5450 on the 920 and its up to you if that is worth it.

 

[Magic Carpet]

30w is big, but my 920 was with 1.6v 1600 ram and a high-end motherboard versus a stock 3750k with 1.35 samsung ram and lower-end mobo.

better go off anand's numbers, which show 7w difference. add another 8 watts for a 5450 on the 950 and its up to you if that is worth it.

My personal experience somewhat mimics this: this

Same video card, hard drive, psu... just different cpu/board nets me a ~50w difference in idle.

GA-X58A-UD3R w/ i7 950 (2x2 GB RAM)
GF 520

~90w

vs

GA-Z77M-D3H w/ Celeron G540 (2x2 GB RAM)
GF 520

~40w

Certainly, the full-size board w/ extra features will consume more power but for HTPC/home server duties, any 1366 socket board is a waste, imo.

 

[coffeejunkee]

30w is big, but my 920 was with 1.6v 1600 ram and a high-end motherboard versus a stock 3750k with 1.35 samsung ram and lower-end mobo.

better go off anand's numbers, which show 7w difference. add another 8 watts for a 5450 on the 920 and its up to you if that is worth it.

Well, I could have found out myself idle board power for the 6950 is 20W.

But then I think your numbers are quite high, 88W minus 20W is 68W. While my P8Z77-M Pro uses less than 45W running the igp (and around 75 using my 5850 which is in line with Ati stated 30W board power).

I expect a simpler motherboard than mine could shave of 10W or even more.

@Magic Carpet: those idle numbers for the Bloomfield systems seem so high...I'm suspecting C-states are not enabled (which a lot of X58 boards don't enable by default). For the 3960X I'm thinking the same, although most X79 boards do not disable C-states afaik. But 180W just can't be right. Here: http://www.anandtech.com/show/5271/gigabyte-gax79ud3-review/4 power usage is 120W with 2 5850's. Subtract 30W and it's 90W with 1 5850 which sounds about right.

 

[Makaveli]

Certainly, the full-size board w/ extra features will consume more power but for HTPC/home server duties, any 1366 socket board is a waste, imo.

For an HTPC I agree for a home server disagree!

Well, I could have found out myself idle board power for the 6950 is 20W.

But then I think your numbers are quite high, 88W minus 20W is 68W. While my P8Z77-M Pro uses less than 45W running the igp (and around 75 using my 5850 which is in line with Ati stated 30W board power).

I expect a simpler motherboard than mine could shave of 10W or even more.

@Magic Carpet: those idle numbers for the Bloomfield systems seem so high...I'm suspecting C-states are not enabled (which a lot of X58 boards don't enable by default). For the 3960X I'm thinking the same, although most X79 boards do not disable C-states afaik. But 180W just can't be right. Here: http://www.anandtech.com/show/5271/gigabyte-gax79ud3-review/4 power usage is 120W with 2 5850's. Subtract 30W and it's 90W with 1 5850 which sounds about right.

Agreed most overclocks that i've seen on site like Hardocp as well they disable all the power saving features.

My overclock has speedstep on and pretty much everything to downclock when no load is detected.