Unlocked E5-1600s?

[XeonOverclocker]

Based on what I have always been told, you can overclock an E5-1600 Xeon of any architecture as long as it uses the same die as the enthusiast i7 chips. For example, because an E5-1660 v2 uses the same 6-core Ivy Bridge-EP die as the i7-4820K, 4930K, and 4960X, it can be overclocked on a motherboard that supports unlocked multipliers. I guess Intel never bothered to disable that feature. Generally, this isn't the best idea, since it's unlikely that a Xeon will be cheaper or have more cores than its i7 equivalent.

But then things get weird. There is absolutely no reason for the 10-core or 12-core Ivy Bridge-EP dies to even be unlocked - they aren't used in any "officially" unlocked CPUs, yet the 8-core E5-1680 v2 (almost certainly cut from a 10-core die) apparently can be overclocked and reach some pretty decent speeds (~4.5GHz). It doesn't even look like this is an engineer sample, but rather the final retail product! It's arguably a better upgrade to drop in one of those into an existing X79 system instead of upgrading to X99 and a 5960X.

The 12-core die doesn't seem to appear in the E5-1600 v2 line-up, so that one probably lacks any unlocked models.

(Source: OCN thread titled "PSA: unlocked 8core for x79.. if you cared." - sorry, can't post links!)


And finally, when asked in an email about this topic, Intel responded that only K chips are unlocked, blah blah blah, generic response. Here's the important part:

"There are no Intel® Xeon processors of E5 family with unlocked multiplier. All processors with unlocked multiplier have the letter «K» at the end of the processor number – example: Intel® Core I7-2600K."

(Source: OCN thread titled "The mystery behind Unlocked Xeons")

[Guest]

No matter what Intel says, I can tell you these are unlocked for sure. I have used/tested a lot of Xeon E5 1600 series, V1, V2 and V3 and 1650, 1660, 1680 SKUs are unlocked.