Intel vs. AMD: Does the CPU really matter?

With the knowledge in hand that AMD was announcing their Opteron 6000 series of CPUs this week in response to last week's release of Intel's 5600 Xeon, I started talking to the folks responsible for actually making the purchasing decisions for a few large SMB customers as well as consultants to Fortune 500-size datacenter customers.   I asked them one simple question; does the processor in the box affect the purchase decision?

The answer was a mixed bag, but boiled down to this; maybe.

Unsurprisingly, much of the interest in these two new CPU releases depended upon the point in the equipment replacement cycle of the IT guy I asked.  A common thread was the sit back and watch attitude, though everyone was excited, if that is  the right word, to move their 1P to 4P servers to these new, higher core count, higher performance, CPUs, when the opportunity presented itself.  These folks have the luxury of watching the market and the media and making use of the information that appears about the performance and value of the two platforms over the next few months.

One IT guy I talked to put it very succinctly; "I don't have a dog in this race. My job is to spend my budget as effectively as possible." He didn't care which processor was in the box; he only buys from top tier server vendors and for his area of responsibility, squeezing the last erg of performance out of a server wasn't really the concern; stability, reliability, and meeting the less compute-intensive needs of his business unit were the driving factor.

"My job is to spend my budget as effectively as possible"

Contrast this with the director of a database server computing unit I spoke with. In his case he was a diehard Intel fan and his belief was that even with more cores, the AMD CPUs wouldn't deliver the performance of the new Intel processors, but he was hedging his bets. He did plan to evaluate the offerings from his vendor of choice to determine if the larger number of cores would make a difference in his environment.

Given that AMD seems to have chosen to focus on value and energy efficiency, it is likely that his testing will still show that the Xeon 5600 series will hold an edge, in his application, over the Opteron 6000.

For really serious interest in the potential of the AMD 8 and 12 core processors I had to step out of the large datacenter space to the guys that buy only a few servers at a time. For IT folks supporting smaller server groups they expressed interest in seeing published performance numbers for these new CPUs and a willingness to purchase if they were a good value for their more tightly constrained budgets.

Bigger datacenter managers didn't really focus on the buy-in cost of their new servers. They have far more interest in the ongoing expenses related to the servers, and as most of the ones I know tend to buy from a specific server vendor, they already have an excellent idea of the projected costs of their server platforms over the usable life of the hardware. When viewed from this perspective, the price delta between the Intel and AMD offerings isn't really significant.

Energy utilization in this scenario has the potential to be a purchasing issue, but evaluating the actual energy consumption of the servers in real-world use is going to be a much more difficult metric to define.  While the power consumption numbers of the processors are clear, the value of the power vs. workload metric, for any specific user scenario, is rarely easily seen, especially in short term testing.

One group I really haven't been able to get feedback from yet are those that use software with per-core, as opposed to per CPU licensing. Doubling or tripling the number of cores in their servers could have a very deleterious effect on their budget numbers regardless of performance improvements. Users of Microsoft server OSes don't need to worry; their license is per processor, not per core. VMware licenses currently allow up to 12 cores per processor, so for the moment, VMware users are also unaffected. Following up on this for software that is still licensed per core will need to wait for a later post.

It's been a long time since the CPU was the sole deciding choice for a server platform in major business. The package delivered from the server vendor; that combination of price, support, experience, and reliability, is usually much more important than the vendor name that appears on the CPU.