ck's archive: the math i forgot

I'd meant to include this in yesterday's criticism of Sun's "CoolThreads" architecture, so here it is now:

The fastest T1 processor that Sun sells right now has eight 1.2 GHz cores, so if everything is loaded at its theoretical maximum, it can do ~9.6 billion computational cycles a second.

Sun also sells the Sun Fire X4200, which uses Opteron chips. The baddest-assed X4200 sports a pair of dual-core Opteron 275s at 2.2 GHz. When it's got all its pipelines filled , it can do ~8.8 billion cycles a second.

On paper, it looks like the T1 is winning, but there are a few mitigating factors:

1. The Opteron can process more instructions in each clock cycle.
2. Each Opteron core has its own 1MB level 2 cache (the T1's eight cores share 3MB among them).
3. Each Opteron core contains its own floating point unit that's proven quite impressive (the T1's eight cores share a single FPU that's not nearly as capable).
4. Four processors is easier to schedule for than 32.

...and the cost of the two servers:

1. Top-of-the-line T2000: $26,995.00
2. Top-of-the-line X4200: $5,645.00

Besides the different processor, the T2000 sports 32GB of ram (vs. the X4200's 4GB), but most of the other components (disks, enclosure, alom) are equivalent. As might be expected, I'm having trouble seeing why it'd be worth the cost. If I missed anything, let me know; I'm open to suggestion.