Does Woodcrest's 25% higher FSB make it faster than Conroe??

IntelUser2000

Elite Member
Oct 14, 2003
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The answer is no. It's the other way around.


http://www.tomshardware.co.uk/2006/06/2...odcrest_preys_on_opteron_uk/page2.html

Check out the memory bandwidth benchmark. Quad channel is needed to match Core 2 systems' memory bandwidth using only dual channel. Dual channel on Xeon 5100 drops to approximately 68% of the quad channel bandwidth. That in numbers is 3.8GB/sec. Not to mention Xeon 5100 series has 25% higher memory FSB. It needs 25% higher FSB and 2x memory channels to achieve the same memory bandwidth numbers the desktop Core 2's can. According to memory latency benchmarks, the latency is also significantly higher on the Woodcrest than Conroe's platform.

The chipset on the Xeon 5100 is worse in performance than the chipset on the Core 2. It will NOT beat Core 2 because of the 25% higher FSB, it will rather be SLOWER. Not to mention FB-DIMM makes it even slower.

SpecFP benchmarks also support this:
Xeon 5160(3GHz/1333MHz FSB/4MB L2/8x1024MB FB-DIMM DDR2-667): 2775
Core 2 Extreme X6800(2.93GHz/1066MHz FSB/4MB L2/2x1024MB DDR2-800 5-5-5-15): 3046

Core 2 Extreme gets almost 10% higher in the memory subsytem sensitive portion of the SpecCPU 2K. benchmark, even though it has 2.2% less clock speed than the Xeon 5160.

Look here: http://www.anandtech.com/IT/showdoc.aspx?i=2772&p=4

"ScienceMark didn't agree completely and reported about 65-70 ns latency on the Opteron system and 70-76 ns (230 cycles) on the Woodcrest system. We have reason to believe that Woodcrest's latency is closer to what LMBench reports: the excellent prefetchers are hiding the true latency numbers from Sciencemark. It must also be said that the measurements for the Opteron on the Opteron are only for the local memory, not the remote memory."

Xeon 5160 got 70-76ns in ScienceMark, what did Core 2 get?? It got 36.75. Xeon 5160's ScienceMark latency is higher than Pentium Extreme Edition 965's latency, and twice the latency of Core 2.

Everest shows the same thing: http://pc.watch.impress.co.jp/docs/2006/0801/graph6.htm

Xeon 5160: 99.1
Opteron 285: 57.7(seems higher than FX-62 results but this system uses Registered DDR DIMM, you can see in AT's results that AM2 further lowers latency)

Core 2 Extreme: 59.8
http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2795&p=5



Not to mention Xeon 5100 platform is more expensive. If you wanna get Xeon for the 1333MHz FSB, well... don't, get Core 2. You can get even lower latency DDR2, giving further advantage in favor of Core 2 over Xeon 5100. If you want SMP support, well, you have no choice then Xeon, otherwise, Core 2 performs better.