JF-AMD

I think this helps underscore my point. Sometimes you get performance, sometimes you don't.

I used to work for a major OEM that sold Intel systems. One of the biggest problems was that SQL Server, for instance, ran slower with HT when you had more than 4 threads.

But customers never thought to turn it off because they assumed it was a "performance feature." If it was pitched as a "sometimes" performance feature, then people might be inclined to turn it off to check performance.

If I had a dollar for every customer I had to have that discussion with, I could have bought myself a server.

The goal was not to dismiss SMT - merely to explain why we are not using it.

We have a different strategy than the competition. They are choosing SMT, we are heading down the path of more physical cores.

At the end of the day 3 things matter: what is the performance (throughput), what is the power consumption, and what is the price.

I am pretty confident we will do well in all 3.

The argument that we have been deflecting for some time is "SMT only adds ~5% overhead and gives you ~20% more performance." On the surface that sounds like a good tradeoff. If you always got 20% - but you don't.

Instead, for our Bulldozer product, we are using 16 cores. It will be in approximately the same power/thermal range of our current 4 and 6-core products. But 2 threads running on 2 physical cores will deliver 80% more throughput than 1 thread running on 1 core. When you compare that to the 20% uplift for SMT when you run 2 threads on 1 core, you start to see the benefit.

Ah, welcome to the world of lawyers. Those disclaimers are everywhere, like the the labels on the lawnmowers that say "don't pick this up while it is running." They aren't distancing themselves from me, just standard legal stuff.

Yes, it is marketing, but my job is marketing.

You are definitely right that CPU is not always the problem, some systems can be I/O or memory-bound.

Our 4 channels of memory on the new products will help with the latter; to fix the former, you need OEMs willing to put down mulitple chipsets. Typically the cost drives people away from those designs, unfortunately.

I will get that fixed. Thanks.

No, it has more to do with the inconsistency of SMT in an x86 environment. If we were always getting consistent performance gains and expected stability it would be a consideration. That might change in the future, but the technology needs to refine first.

We have looked into that, but that is not our strategy. If we knew that SMT (in an x86 architecture) could lead to an "always better performance" environment, it might be more applealing. But the fact that the performance aspect becomes application dependent (and there are possible stability situations), we defer to no SMT.

If future implementations do a better job it would be something to consider.

For now we believe that actual cores will drive better performance. If I can put 12 cores into the same price and power envelopes (or even lower) as my competitor's 6-core with SMT, I end up with a better processor.

Cores vs. SMT breaks down if your cores are consuming significantly more power or you are driving your cost up. But if you are not doing those things, than cores over SMT becomes the right call.

no, that was actually not a pun.