On 2020-08-17 13:30, James Allsopp wrote:
Hi,
I'm using an old Core 2 processor in a case with 5 hard drives, one of
which is an SSD. It's a server but doesn't get hit particularly hard, so
I'm wondering what the options are to try and conserve power with it as
it's generating rather a lot of heat. I've looked at powertop, but there
didn't seem to be a huge amount there.The processor only scales between 2
and 3Ghz with an ondemand governor. I upgraded the processor from a E8460
and doubled the ram to 8GB, with the same hard drives and this was when I
noticed the temperature increase.
I assume you verified that the motherboard is rated for the upgraded
CPU, the CPU heat sink/ fan is rated for the upgraded CPU, you used good
(silver) thermal compound, the power supply is rated for the connected
load, the internal cables are bundled/ routed to keep air pathways
clear, and you vacuumed the inside of the case, heat sinks, fans, etc.?
I do not see a Core 2 "E8460" processor on the Intel web site. The Core
2 Duo E8400 has a TDP of 65 W [1].
The Core 2 Quad Q9650 is 95 W [2]. So, 30 W more. The motherboard
voltage regulators must supply the increased load at whatever efficiency
they have and the PSU must supply both increases and whatever efficient
it has.
DDR modules are ~3 W each [3]. Two more would add 6 W. Again,
motherboard and PSU.
Assuming a "regular motherboard" and 80% efficient PSU, here is a power
estimate for the original configuration [3]:
processor 65 W
2 @ DDR3 memory 6 W
CPU & memory 71 W
motherboard 40 W
no video card 0 W
1 @ SSD 3 W
4 @ HDD 32 W
2 @ fans 4 W
usage 150 W
80 Plus PSU 38 W
total 188 W
And, for the upgraded configuration (scaling up motherboard consumption
in direct proportion to CPU and memory consumption):
processor 95 W
4 @ DDR3 memory 12 W
CPU & memory 107 W
motherboard 60 W
no video card 0 W
1 @ SSD 3 W
4 @ HDD 32 W
1 @ fans 4 W
usage 206 W
80 Plus PSU 52 W
total 258 W
So, a total power increase of 70 W, or 38%.
What temperature sensor readings have you observed before and after the
upgrade?
Assuming the machine is intended to run 24x7, ideas to reduce power
consumption:
1. Install the package 'cpufrequtils', which provides cpufreq-info(1)
and and cpufreq-set(1). (It sounds like you already have done this?)
To see what governors are available:
# cpufreq-info -c 0
Pick a governor that can lower the CPU frequency -- for example on
my system, it is 'powersave':
# cpufreq-set -g powersave
2. Set the CPU frequency upper limit manually:
# cpufreq-set -u 2000000
3. Tune system and/or daemons not to periodically access the drives.
This implies determining what processes periodically access the drives
and determining if they offer drive access options.
4. Mount file systems with the option 'relatime' or 'noatime'. This
implies determining what processes use what file systems, and whether or
not they can tolerate atime settings. See fstab(5) and mount(8).
5. Tune the drives to enter power saving mode when not in use. Again,
verify that processes can tolerate those settings. See hdparm(8).
6. Tune the motherboard firmware to use fewer CPU cores, to lower the
CPU/ memory frequency, etc.. Even if you go back to 2 cores, the Q9650
has twice the cache of the E8400 and should perform better at the same
frequency.
David
[1]
https://ark.intel.com/content/www/us/en/ark/products/33910/intel-core-2-d
[2]
https://ark.intel.com/content/www/us/en/ark/products/35428/intel-core-2-quad-processor-q9650-12m-cache-3-00-ghz-1333-mhz-fsb.html
[3] http://www.buildcomputers.net/power-consumption-of-pc-components.html
