Undervolting the AMD 240e: Can it run passively? Best mobo?

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tkorsvold
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Undervolting the AMD 240e: Can it run passively? Best mobo?

Post by tkorsvold » Wed Sep 23, 2009 3:17 am

Hello,

I've been looking at a new HTPC lately, these are the parts:

CPU: Athlon II 240e (when it becomes available)
Mobo: Don't know yet
RAM: Don't know yet
Case: Silverstone SG02
Hard drive: Samsung EcoGreen F2 500GB
PSU: Nexus Value 430
CPU Cooler: Scythe Big Shuriken


I'd like to undervolt the RAM and the CPU as much as possible.
My goal is to cool the CPU passively.
What would be the best Motherboard for the task?
And which RAM runs coolest / needs the least voltage?

I might also consider an add-in ATI 4670 (passively cooled) for graphics.
So I'm not necessarily restricted to 785G motherboards.

Any help appreciated!

Thorstein

barefootzero
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Post by barefootzero » Thu Sep 24, 2009 1:18 pm

There is one problem with your build. Well maybe 2.

Why are you trying to run a fanless CPU with a fan cooled PSU?

Just for the sake of some perspective and given that my HTPC rig is similar to what you planned though using a undervolted 240...
* while web browsing my HTPC uses 34 watts at the outlet.
* At peak load (prime95 + Fur Mark) my system draws 88W

My PSU is a DC-DC adapter from electrodacus with 24V brick from so the only fan I have is the one on the stock CPU HSF and at idle or web browsing it is very quiet. You could use a PicoPSU but for a variety of reasons I like electrodacus's product better.

The CPU fan in my setup takes air from outside the case so it also serves as a case fan. I think this works very well and is very close to silent and the fan noise is roughly comparable to the seek noise from my Fujitsu mhv2120ah 120GB 5400rpm laptop drive. Unless you move to a SSD I think it would be hard to get much quieter then my rig.

The second problem is that for a completely passive system I would use a laptop drive. The EcoGreen F2 is pretty low power but if you aren't going to use any fans at all I would still prefer a laptop drive which will run cooler.

For the record my system specs are as follows
CPU: Athlon II 240
Mobo: MSI 785GM-E65 (I really like this board)
RAM: 2x2GB DDR3 1333 Crucial CT2KIT25664BA1339
Case: Custom Card Board (working on a permanent wood case)
Hard drive: Fujitsu mhv2120ah 120GB 5400rpm 2.5" drive
PSU: electrodacus 130W DC-DC with salvaged 24V 90W NEC LCD brick.

The cardboard case was a really good idea and in the process of making it I learned some things that will help me with the permanent case.

spookmineer
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Post by spookmineer » Thu Sep 24, 2009 3:40 pm

barefootzero wrote:The cardboard case was a really good idea and in the process of making it I learned some things that will help me with the permanent case.
Cardboard case? Is it home made or is it sold anywhere, and do you have pictures of it? (maybe even when installing the hardware?)

barefootzero
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Post by barefootzero » Thu Sep 24, 2009 9:37 pm

moved description to new thread
Last edited by barefootzero on Thu Sep 24, 2009 10:05 pm, edited 1 time in total.

barefootzero
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Post by barefootzero » Thu Sep 24, 2009 9:59 pm

I moved the description and posted some pictures in a new thread so as to not hijack this one.

viewtopic.php?p=482394#482394

hans007
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Post by hans007 » Sun Oct 04, 2009 11:23 pm

i have my athlon ii x2 240 undervolted to 1.175V on a j&w minix 780g. Pretty hard to find, but its a great htpc board.

barefootzero
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Post by barefootzero » Mon Oct 05, 2009 11:18 am

I also run my 240 at 1.175V. Anything below that was unstable. I also noticed when testing the 250 SPCR undervolted to 1.175. I wonder what is magic about that number.

The board you found looks nifty though I for the price I think I might have gone over to the intel camp in order to go mini-itx. Maybe get a nvidia board and an e3300

http://www.jwele.com/motherboard_detail.php?419

jhhoffma
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Post by jhhoffma » Tue Oct 06, 2009 5:00 am

barefootzero wrote:Why are you trying to run a fanless CPU with a fan cooled PSU?
Why not? Many people run their setups this way, including me.

The CPU fan is often a much larger source of noise than a PSU fan due to the usual stock speed. Also, in most ATX cases, the CPU is usually located very close to the exhaust fan, making it ideal for passive cooling when using a large tower heatsink. Whereas, an actively-cooled PSU needs it's own directed airflow.

barefootzero
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Post by barefootzero » Tue Oct 06, 2009 8:01 am

jhhoffma wrote:
barefootzero wrote:Why are you trying to run a fanless CPU with a fan cooled PSU?
Why not? Many people run their setups this way, including me.

The CPU fan is often a much larger source of noise than a PSU fan due to the usual stock speed. Also, in most ATX cases, the CPU is usually located very close to the exhaust fan, making it ideal for passive cooling when using a large tower heatsink. Whereas, an actively-cooled PSU needs it's own directed airflow.
I consider it a matter of control. It is far easier to get a mother board that has good fan control and match it with a cpu fan that is quiet then to find a PSU that has good fan regulation and a quiet fan. Also making the PSU fan suck in a bunch of hot air will make the PSU run louder. It is better to configure the PSU to get cool air and vent the CPU and system heat else where.

Additionally the OP plans on using a very low power CPU and a generally low power setup which means the system can get by with a PSU like electrodacus or minibox sells.

In his sort of system using a brick and adapter like electrodacus or minibox sells combined with a cpu fan ducted to take cool air from outside the system can be a much quieter solution. My system which is somewhat similar to his (athlon 240 with integrated graphics) and is configured this way and runs very quietly at idle (below ambient). When the CPU is fully loaded it makes a bit of a whoosh noise but as a HTPC it almost never really loaded. With a better HSF I am sure it could be practically inaudible. The only compromise might be to switch the desktop drive to a laptop drive that will run a little cooler in a low air flow environment.

Finally the OP didn't ask "how do I cool my CPU with the PSU fan". He asked about the prospect of passively cooling a CPU. I really get sick of people on these forums responding to these posts with stories about their "passively" cooled CPU that are really cooled by the PSU fan or a case fan. That is by definition not passive. If it was I suppose I could say my CPU is passively cooled by the "system fan" that just happens to be sitting directly on top of the CPU heatsink :!:

coreyography
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Post by coreyography » Tue Oct 06, 2009 7:11 pm

Regarding another aspect, what OS will you be running your HTPC on? If it's Linux, you might want to consider NVidia graphics instead. From what I've been reading the state of the proprietary ATI Linux driver is hit or miss, and even though they are (slowly) releasing docs for their cards, the open-source drivers don't fully utilize the power of their latest GPUs yet.

I bought an ATI board for my Linux desktop setup, wanting to support them in their new cooperative spirit and all, but I just can't get Catalyst to work. Alas, altruism has given way to practicality, and I'm running the Xorg driver until my GTX275 shows up. I'll probably buy a fanless GeForce 8000 or 9000 series card for my girlfriend's HTPC too (NVidia VDPAU seems farther along in Linux than any ATI equivalent). Too bad, because those 785G boards look nice.

tkorsvold
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Post by tkorsvold » Wed Oct 07, 2009 2:54 am

I ordered all the components a couple of days ago, made a few changes:

- CPU: AMD Sempron X1 140 (I am planning to unlock the second core, and undervolt the CPU)
- CPU cooler: Scythe Ninja (hopefully this is good enough for passive cooling)
- 4GB DDR3 RAM: 2 sticks of 1.5V DDR3 1333MhZ, will try to undervolt
- Motherboard: MSI 785GM-E65
- Hard drive: Samsung EcoGreen F2 500GB (single platter for minimal noise)
- PSU: I have ordered Electrodacus' power supply plus a good power brick.
- Aopen BDR0412SA blu-ray drive
- Point of View M2 Micro-ATX case
- OS: Windows 7

I'll give you some feedback on the results once I get the components!

Ksanderash
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Post by Ksanderash » Wed Oct 07, 2009 4:59 am

tkorsvold
Btw, have you the kill-a-watt thing or something else for measuring needs? You'll need something to show us your under 30W at the outlet consumption ;)

barefootzero
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Post by barefootzero » Wed Oct 07, 2009 12:52 pm

tkorsvold wrote:I ordered all the components a couple of days ago, made a few changes:

- CPU: AMD Sempron X1 140 (I am planning to unlock the second core, and undervolt the CPU)
- CPU cooler: Scythe Ninja (hopefully this is good enough for passive cooling)
- 4GB DDR3 RAM: 2 sticks of 1.5V DDR3 1333MhZ, will try to undervolt
- Motherboard: MSI 785GM-E65
- Hard drive: Samsung EcoGreen F2 500GB (single platter for minimal noise)
- PSU: I have ordered Electrodacus' power supply plus a good power brick.
- Aopen BDR0412SA blu-ray drive
- Point of View M2 Micro-ATX case
- OS: Windows 7

I'll give you some feedback on the results once I get the components!
Looks good. I am interested to know how that heat sink works out for you. I have been thinking about upgrading from the stock cooler on my rig but I only want to do it if I can go totally passive.

JamieG
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Post by JamieG » Wed Oct 07, 2009 3:17 pm

I don't understand this obsession with passive CPU coolers. A low RPM fan at 5V is virtually inaudible and will make a noticeable difference in your CPU temps.

I've tried this with my undervolted E5200 at 2Ghz in an open motherboard tray just sitting on my desk and full load CPU temps with a HR-01+ running passively without any cooling whatsoever are about 8 to 10C higher than with a Slipstream 800rpm at 5V mounted on the heatsink.

Besides, if you are mounting your motherboard in a case with a rear exhaust fan, this isn't really passive cooling, not with an exhaust fan pulling some air through the CPU cooler from a few centimetres away.

Anyway, with your low power CPU and a nearby rear exhaust fan, you should be able to run the Ninja without a fan on it if you want to.

Greg F.
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Post by Greg F. » Wed Oct 07, 2009 3:52 pm

I've run a Ninja passive in a TF8200/AMD 4000x2 OCd to 2.6. In the winter. In the summer, no. But like Jamie, I just didn't see the point. I have an Asus 75 on that board now and the fan is off right now. If I start doing more things the fan will come on, but it is not intrusive.

barefootzero
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Post by barefootzero » Fri Oct 09, 2009 8:47 am

JamieG wrote:I don't understand this obsession with passive CPU coolers. A low RPM fan at 5V is virtually inaudible and will make a noticeable difference in your CPU temps.
For me its more of a design challenge then anything else. I have tried a couple times to make a totally passive system using relatively normal parts (no C7 and no super expensive cases etc) but always needed at least one fan.

tkorsvold
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Post by tkorsvold » Sat Oct 10, 2009 1:00 am

My goal is to run passively, but I like to take a pragmatic approach.

So if I can run a CPU fan at low RPM - and it really IS inaudible, well then that's fine :-)


Thorstein

loimlo
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Post by loimlo » Sat Oct 10, 2009 2:14 am

It's very easy to cool my 65W X2 245 with a fan rotating 390RPM on Xigmatek 1283, let alone 45W 240e. I've been deeply impressed by 40nm dual core CPU and Xigmatek tower design cooler. Based on my experience, couple a good cooler with a quiet fan would do a better job at cooling CPU compared to passive cooling without sacrificing silence. Frankly speaking, the loudest component in my computer is HDD's seeking noise. I can't hear the fan running inside P182.

Room ambient: 21'c
Image

aleutia
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Attempt at passively cooling Sempron 140

Post by aleutia » Sat Oct 24, 2009 1:42 am

Hadn't been aware of the 240e (I really miss the 4850e and 5050e) - thanks tkorsvold for pointing me to it.

I tried passively cooling the Sempron 140 with $7 Akasa AK-CC032 heatsink and thought you'd enjoy the video (google: passively cooled amd 140)

This is pretty basic (no heatpipes) and predictably temperature sky rockets to about 80 C. I think you should stay focused on passively cooling your system but what's interesting here is that a large fan at 300 rpm will actually keep temperatures in control and is pretty quiet. Unfortunately the combo won't fit in the minibox m-350 case we use. :(

Note: I also put a scythe shuriken (3 heatpipes) on it and removed the fan and story was the same. Be curious how the ninja plays out.

Have you thought about a Kingston 64GB SSD? Decent speed and pretty cheap (about £100 online here in the UK).

Justchill
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Post by Justchill » Fri Jan 01, 2010 4:46 pm

Hi,

just wondering, how did you guys undervolt the X2 240 ? I cannot do it in the BIOS...

Esben
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Post by Esben » Mon Jan 04, 2010 3:00 pm

Use the application k10stat. You might want to look at this article for a primer on undervolting your CPU.

hans007
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Post by hans007 » Mon Jan 04, 2010 6:37 pm

i actually eventually ended up swapping out my 240 for a 235e...


it uses something like 2 watts-3 watt under idle than the 240 did undervolted so there might be something else there.

you can get a 235e on ebay for under $60 sometimes especially with the bing cash.

grandpatzer
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Post by grandpatzer » Fri Apr 09, 2010 1:29 am

hans007 wrote:i actually eventually ended up swapping out my 240 for a 235e...


it uses something like 2 watts-3 watt under idle than the 240 did undervolted so there might be something else there.

you can get a 235e on ebay for under $60 sometimes especially with the bing cash.
does your post mean that the 235e only is 2-3watt less in idle compared to 240?

in that case I will propably just get a 240 and undervolt it.

goofee
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Post by goofee » Tue May 04, 2010 2:44 am

I recently exchanged my 4850e for a 240e. It runs passively fine with the scythe ninja mini cooler, but i have two noctua 12cm fans in the case as well for some airflow. But it's noiseless from 1m and out basically.

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