More CPUs/Cores compared to higher clock speed?

Thomas P

Member
Hello

we currently use one Nehalem/Bloomfield CPU @ 3,06 Ghz and 4 Cores on our Server and would switch to a SMP-CPU Setup with two Xeon CPUs Gulftown/Westmere-EP @ 2.13 Ghz and 8 Cores.

Any thoughts on switching from Single-CPU to Multi-CPU at lower clock speed?
Which im impact would that have on serving XenForo?

Thanks
 
The main thing to bear in mind that that for mySQL in particular, its not multi-threaded for single actions - i.e. it doesn't multithread for a single query, but of course it spawns multiple workers so more cores mean more threads can be served, but if the clock rate is slower, then potientially the individual queries would get served slower, although it could do more of them at once.

its swings and roundabouts at the end of the day, you gain on coping with multiple loads, but potientally loose out on actual processing speed.

Multi cores do cope with server loads better though, in my experience, although naturally it increases the load on the rest of the subsystem, hard drives, ram etc..

Although according to CPUBenchmark, the difference between a W3550 and L5640 (the one up from yours as they don't have the 2.13Ghz chip) is reasonable (5,598 vs 7,709) so it would appear that the CPU is faster in any case, even with the drop in raw MHz.
 
For the most part if running mysql then more speed is better than more cores past 4 cores, if running mssql then cores are better than speed.

Obviously it also depends on how much load your server comes under :)
 
Thanks guys - how about PHP processing?

What are you running, apache, nginx, cherokee?

If configured correctly, all of your handlers will run better on multi-cores over top end speed. But it depends how savvy you are with making the best out of multi core situations, eg configuring each worker to ONLY use a seperate core from the others.
 
On my server mysql is very fast but php slows down everything. I took a new cpu with much higher cpu ratings and it speeds everything up.
 
I went from four cores i7 to four cores i7 but the cpu speed is faster and page generation time dropped around 30% (more or less).
 
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