ULV versus LV versus standard voltage CPUs. Performance difference?

[josh1980]

Anyone seen any reviews that compare the performance between the standard volt, ULV and LV CPUs for performance and efficiency?

I know that often the ULV or LV have different cache sizes and frequencies and the ULV and LV are typically used in positions that aren't exactly "high performance". I was just wondering if anyone either has tested themself or seen a review comparing the 3 and has numbers for the differences.

[jcool]

ULV and LV chips are binned for low TDP. Additonally, they run at slower clockspeeds than normal CPUs and use less Vcore, but even if you were to overclock an LV chip it would still use less Watts than most standard CPUs. It's what you may know as low-VID and high-VID chips: High VID CPUs usually need more Vcore to overclock, but generally run rather cool because they tend to have little leak currents. Low VID chips require less Vcore and usually OC better, but run hotter and draw more power at identical voltages.

So LV and ULVs are basically undervolted and strictly binned high VID CPUs. Performance of those CPUs is usually equal to standard CPUs (assuming they run at the same clock speeds) - since they are usually clocked lower, they are slower by the amount of mhz "missing" to the standard models.

[josh1980]

I figured the same thing, but I was looking for numbers that show the differences. I was wanting to know by how much things are better versus the different types :P. Allegedly the ULV and LV are not the identical design to their "standard" counterparts, or even to themselves. I have a family member that works at Intel, so I get a little inside info here and there.

[jcool]

The only L CPUs I have right now (besides the Sossamans) are L5640 Hexacores.
They are perfectly identical in performance to my X series hexas (provided I overclock them) but pull notably less power from the wall.
IIRC between the X5650 and L5640 (both running at 3,8Ghz with 1,25V Vcore on WCG) the difference was around 40W from the wall.

Maybe there are differences in the manufacturing process in some cases, but in this case I don't think so. The L5640 is just really REALLY well-binned.