<$100 2core Athlon II AMD? X2 240e? or undervolt X2 250?

[morkys]

What's the best value AMD dual-core AM3 CPU under $100 (CDN) for combination of low power and fast processing speeds? Going to use the MSI 785GM-E65 main board.

Should I get an e CPU and undervolt/tinker or should I get a regular Athlon II and undervolt. I see mixed responses. Some people say the e CPU's are better, and use less power than undervolting an equivalent non-e CPU, while others say you don't save much power.

For example, here are a few different CPU's I could use with the MSI 785GM-E65:

Athlon II 240 $66, 245 $71, 250 $76
Athlon II 235e $79, 240e $89

Could I undervolt the X2 250 and get the power down to the level of the 240e? ...or would that require underclocking too?

Any thoughts?

[Greg F.]

I am going to resurrect this older thread rather than start a new one about the same subject.
I know Mike C. uses a 240e in his HTPC, or he did a short while ago. But where are these cpus being sold? There are lots of articles at various websites, but none for sale that I can see.
And what about "morkys" question? I too would like to know if undervolting a 240 would yield the same results as an "e" model as far as total system power consumption.

*Also living off the grid at 3kwh per day.

[flyingsherpa]

I just bought one from buy.com, it should arrive any day now. Looks like they are still in stock. Kind of a premium over a regular 240, but I wanted to check it out. I'm sure many/most 240's can undervolt well, but it could be hit or miss and I didn't want to deal with the hassle.

[zodaex]

The AMD 45W CPUs are around, it's just that Newegg doesn't have them for some reason. I like them a lot because it saves me a week of undervolting/stress testing my cpu so it's worth the extra 20 bucks to me. My CPU in my sig computer cost 30 bux shipped.

[greenfrank]

the "e" processors are hard to find, in my experience. Maybe are slightly better, but "regular" athlons if undervolted can perform also very well in power consumption.
My Athlon II 240 x2 rig is 30w idle only.

[SleepyBum]

the "e" processors are hard to find, in my experience. Maybe are slightly better, but "regular" athlons if undervolted can perform also very well in power consumption.

Yes... the "e" processors are just cherry picked. The regular ones can undervolt to about the same level. Also, like greenfrank said, they are hard to find. I think someone on here said Tigerdirect carried them, but there was about a 30% mark up over regular non-"e".

This is what I can get on my Athlon II X2 250:

in a Shuttle SA76G2 barebone
AMD 760G + SB710

There is no FSB or voltage control in BIOS so all undervolting was done in K10stat

Stock: 3000Mhz 1.440V

Speed __ K10stat CPU-Z
3000Mhz 1.1500V 1.168V
2800Mhz 1.0875V 1.104V
2200Mhz 0.9500V 0.976V
1500Mhz 0.8000V 0.816V
0800Mhz 0.6750V 0.688V



There was an article on the 240e:

AMD Athlon II X2 245 vs 240e dissected

At stock, the 240e is 1.240V @ 2800Mhz and 0.920V @ 800Mhz. They further manually undervolted to: 1.040V @ 2800Mhz and 0.816V @ 800Mhz.

So there's even some more room to further undervolt on the "e" chips. The only downside for the regular chip is it has a crazy high voltage at top stock speed, 1.440V. Article even mentions it:

As usual AMD CPUs have an ridiculously high VCore. Why a dual-core CPU needs 1.4250V is beyond our understanding. The so called energy efficient CPUs have a reduced VCore of 1.2500V. Also in idle the voltages are quite high. We don't like that at all.

So even if you get an "e" chip, there's still further undervolting to be done. The only benefit I can see if that they could undervolt to 1.040V @ 2800Mhz 240e vs 1.104V @ 2800Mhz regular 250.

[vortex222]

the E cpus are great out of the box. A decent 'no muss no fuss' solution, but still far from what can be had either by undervolting or the normal cpu undervolted.

IMO get what is cheapest and try to undervolt.