http://www.frys-electronics-ads.com/ads/2010/10/08/50182/AMD-Athlon-II-X3-445-Processor

That's the price of an X2 so if you wanted more than the Sargas 140 this is a pretty good deal. 

 

I got one because I just replaced my motherboard so I have an Asus M4A78L-M just sitting here. 

FWIW, I put in the cpu and it unlocked it to a Phenom II X4 B45.  I'll have to prime95 it to be sure it's really ok.

I was (still am) happy just getting 3 cores for the price of 2. 

 

Note that chip has a 95 Watt TDP.  I prefer 45 Watt AMD chips for any always-on box like unRAID..... such as Athlon X2 Dual Core Processor BE-2400.  That 50 Watt difference can cost you $50 a year in your power bill.

Running Prime95 so that all 4 cores are maxed at 100% it's drawing 160 watts from the wall outlet.  I'm guessing that the cpu is burning 140 watts off the 12volt rail.  With both sides of the case off and two external fans blowing directly into the case the cpu is at 57c and the motherboard is 41c.  

 

Before I started the test it was drawing 75 watts from the wall - which isn't so bad actually.  These cpu's throttle back very nicely when idle so I'm not convinced about that $50 for a stock unRAID.  I don't think it would draw much more than an Athlon II X2 when mostly idle.

The TDP is an accurate measure of the max heat generated by the CPU, which is going to give you the Wattage used by the CPU itself.  These are necessary engineering specs, and if they were not accurate, all hell could break loose.  Measuring the Wattage used at the wall whole system is also measuring the power for the mobo (e.g. Northbridge) which is a power hog on many mobos.  The Athlon II only saves about 12-20 Watts when idle at the lowest-power P-state.  The rest of the change you saw is in the mobo.  But the difference between a 45 Watt TDP and 95 Watt TDP Athlon is 50 Watts at load.  At idle, it will be less, but not zero.  Check the specs and see what the highest (P3) P-state specs are for each chip, and the TDP at that state.

 

Plus, you have to load the driver (powernow-k8) and the proper governors to get the Athlon to enter the hogher P-states under Linux.  It doesn't happen by itself.

 

The Athlon X2 BE-2400 in a good mobo (e.g., Biostar TA690G AM2) and 80+ Gold PSU can pull less than 40 Watts from the wall at idle.

12 hours of Prime95 done with no errors.  After stopping Prime95 the watts from the wall went down to 70.  The case has 1 hard drive that was spinning the whole time.  I'm using ubuntu 10.1 to run the test.  Cpu idle temp is 30c using the stock heatsink.

 

At idle, it will be less but not zero.  

No one would expect zero.  How about "the sun's very bright but it's certainly not dark."  

 

The Athlon X2 BE-2400 in a good mobo (e.g., Biostar TA690G AM2) and 80+ Gold PSU can pull less than 40 Watts from the wall at idle.

I bet substituting this Athlon II X3 with your stated mobo and psu would do about the same.  Compare apples to apples.

 

I don't have that CPU, but I did swap an Athlon X2 260 (3.2gHz) and the difference at idle, was 32 Watts at idle in P0, and 21 Watts at idle in P3.  That's apples to apples.  I did not test it with mprime since I was not concerned with load performance since it is never under load.

I don't have that CPU, but I did swap an Athlon X2 260 (3.2gHz) and the difference at idle, was 32 Watts at idle in P0, and 21 Watts at idle in P3.  That's apples to apples.  I did not test it with mprime since I was not concerned with load performance since it is never under load.

 

That's better numbers.  I only did the prime95 because it's a new cpu and I stress them to make sure it's not a dud.  And for this one I wanted to ensure the 4th core was fully functional.  Ok, what's P0 and P3? 

Modern CPUs have P-states that define clock speed, voltage, etc., for different performance levels.  AMD calls it Cool-n-Quiet.

 

P0 is the lowest, or fastest, setting.  That will be full voltage and full clock speed.  Higher P states have lower clock speeds (lower multipliers) and lower voltage.

 

For the Phenom II X4 B50 for example, P0 is 15.5x (3.1gHz) @1.275v, and p3 is 4x (800mHz) at 0.925v.  Northbridge voltage can also vary with the P state.

Are you talking about the vcore?  I admit I'm almost out of my depth with cpu specifics as I never overclock.  The vcore when I was running prime95 was 1.39v and when sitting idle it's 1.04v.

What OS are you running to use prime95?  It sounds like you are running Windows.  The Linux version is mprime, not prime95.

 

If you want to understand power usage, you have to understand P-states and the relationship of Vcore to clock frequency and TDP.  The higher P-states above P0 underclock/undervolt the CPU and northbridge to achieve the heat/power savings.

What OS are you running to use prime95?  It sounds like you are running Windows.  The Linux version is mprime, not prime95.

 

If you want to understand power usage, you have to understand P-states and the relationship of Vcore to clock frequency and TDP.  The higher P-states above P0 underclock/undervolt the CPU and northbridge to achieve the heat/power savings.

 

I'm running ubuntu.  Yep, it's mprime but since most people recognize it by the prime95 name that's what I called it.

 

Ok, so when it says the cpu has a 95 watt max does that mean 95 from the psu at 12v or 95 from the wall at 110v?

Ok, so when it says the cpu has a 95 watt max does that mean 95 from the psu at 12v or 95 from the wall at 110v?

 

Neither.  TDP is Thermal Design Power which means different things to Intel then to AMD.  Intel says "?Thermal Design Power (TDP) should be used for processor thermal solution design targets. The TDP is not the maximum power that the processor can dissipate.?"  But to AMD, TDP it is the maximum power that the CPU can possibly dissipate, based on its electrical usage.

 

Measuring at the wall doesn't tell you anything about the CPU... that is just the aggregate of all juice being used, including the wasted heat in the PSU, the mobo, Northbridge, drives, fans .... everything including the CPU.  Measuring at the wall is only useful as a difference between one configuration and another.

 

For example, my desktop is a 3.1 gHz Phenom II X4 BE, and at full load pulls 178 Watts at the wall, but at idle, in P3, it pulls 84 Watts at the wall .... that's nearly 100 Watts less, but only a part of that difference is from the CPU.