Author

Topic: cpuminer scrypt performance on older Xeon cpu's (Read 1136 times)

newbie
Activity: 18
Merit: 0
Greetings to all.

Sorry for posting this here but due to "newbines" status can not post on the relative thread

Started playing around with the recent cpuminer (2.3.2) and litecoin/scrypt on a spare quad Xeon server i have
I noticed that the performance on the older Xeon@3Ghz is not in par with my quad core2 Q6600@3Ghz
Both machines have 8Gigs of ram, Ubuntu X64 and cpuminer was compiled on each machine

The Q6600 gives me around 6.5 khash/s per core while the Xeon 1.60 khash/s
cpuinfo reports pretty similar bogomips although this is not a true performance measure

i.e Q6600

Quote
processor   : 1
vendor_id   : GenuineIntel
cpu family   : 6
model      : 15
model name   : Intel(R) Core(TM)2 Quad CPU    Q6600  @ 2.40GHz
stepping   : 11
cpu MHz      : 3000.000
cache size   : 4096 KB
physical id   : 0
siblings   : 4
core id      : 1
cpu cores   : 4
apicid      : 1
initial apicid   : 1
fpu      : yes
fpu_exception   : yes
cpuid level   : 10
wp      : yes
flags      : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm tpr_shadow vnmi flexpriority
bogomips   : 5994.00
clflush size   : 64
cache_alignment   : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:



Xeon

Quote
processor   : 1
vendor_id   : GenuineIntel
cpu family   : 15
model      : 4
model name   : Intel(R) Xeon(TM) CPU 3.00GHz
stepping   : 3
cpu MHz      : 2992.877
cache size   : 2048 KB
physical id   : 3
siblings   : 2
core id      : 0
cpu cores   : 1
apicid      : 7
initial apicid   : 7
fpu      : yes
fpu_exception   : yes
cpuid level   : 5
wp      : yes
flags      : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc pebs bts pni dtes64 monitor ds_cpl cid cx16 xtpr
bogomips   : 5985.52
clflush size   : 64
cache_alignment   : 128
address sizes   : 36 bits physical, 48 bits virtual
power management:



The only major difference i can think off is that the Q6600 uses DDR2 while the Xeon older server DDR memory, but i really wonder if that alone could account for the huge performance difference,since both have rather large caches.

One other strange thing i noticed is that cpuminer uses roughly 75% of the core's "power" (Top shows 75% nice 25% idle) in both cases
(Was expecting to  see a 100% nice on the core it was running)

My interest is purely from a dev standpoint as with the the GPU's doing most of the work, the few khash difference per cpu core is nothing in a production system. 


Jump to: