What is the difference between the C0 and E0 stepping in the Intel Xeon 5400 family of processors?

Question

My primary question is in the title, and can be answered as simply as that. However, I think some background information may be relevant.

I'm doing some research into upgrading one of our three year old Dell PE 1950's to be a heavyweight (for a 1U) DB server. The CPUs are currently two entry-level Xeon 5110s (1.6 GHz, Dual Core, "Woodcrest" family).

I've been researching and pricing OEM parts in the Xeon 5400 (2.0 to 3.4 GHz, Quad Core, "Harpertown" family).

In the course of this research I've learned that there are two steppings: C0 and E0, however I can't find many plain-English specifics as to what is different, besides their release dates of Nov. '07 and Aug. '08 respectively. All I can see is "XSAVE/XRSTOR instructions were added", but what does that mean for my needs?

Normally I'd just not care and get the E0 to play it safe because it's the latest & greatest for this family of CPUs. However, I have found some rather significant pricing differences between the C0 and E0 steppings as shown here:

Model   Speed (GHz)  E0 USD x 2  C0 USD x 2
E5405   2.0                 570         560
E5410   2.33                740         520
E5420   2.5                 860        1020
E5430   2.66               1020        1010
E5440   2.83                  ?           ?
E5450   3.0                1560        1580
X5450   3.0                   ?           ?
X5460   3.16                N/A        1020
X5462   2.8                1160        1120 
X5470   3.33               1420         N/A
E5472   3.0                   ?        1430 
X5472   3.0                   ?         740 **
X5482   3.2                   ?        1620

_{? = Could not find price from "reputable" vendor, yet.
Prices are for two CPUs}

Note the cost of the C0 X5472, $740 -- the equivaent of the E0 E5410.

Now, until I priced the X5472 I was leaning towards the E5410 or E5420. However I'd be foolish to ignore the C0 price anomaly.

I'm not going to ask for a recommendation, but I would like to know if that is a misleadingly low price.

• Am I going to see a difference between a C0 and E0 stepping in a MySQL DB server (32 GB RAM if it matters)?
• Am I missing out on any critical functionality? Will it compromise the reliability of my production environment?
• Is this totally worth it? (yes, subjective, but just this! :)

Solution

My understanding is that the "stepping" designators in a specific product line are for denoting minor revisions in the silicon. As they increment the feature set of a specific processor, they increment the stepping number. In the case of the processor you're looking at, it looks like the major difference between C0 and E0 is the max clock rate: 3.00 GHz vs. 3.33 GHz.

Am I going to see a difference between a C0 and E0 stepping in a MySQL DB server (32 GB RAM if it matters)?

Perhaps incremental performance improvements with the E0, but nothing significant.

Am I missing out on any critical functionality? Will it compromise the reliability of my production environment?

Nope, core functionality should be the same between different stepping revisions of the came product.

Is this totally worth it? (yes, subjective, but just this! :)

It's probably not worth spending too much time on.

Comments

[Daniel Lawson]

The X5472 has a max TDP of 120W, which may make it unsuitable for your 1U server. Consider that the X5110 had a max TDP of 65W, and the hottest 51xx processor had a max TDP of 80W. You're adding a not insubstantial amount of heat to your system, so tread carefully. Not relevant to your actual question, I know :)

[Chopper3]

Very good point Daniel - hobodave I can't stress this enough that you shouldn't go over the TDP of the highest TDP CPU available at the time of original server build.