Question : Problem: CPU for 955X chipset

Hi,

I have an Intel D955Xcs mainboard and need help selecting a CPU.  It supports the processors listed below but I am confused.

Any simple way to sort the differances out?  I will be using 32bit XP but if 64bit Cpu's can run 32bit apps fine then there is only a $7.00 diff between the 670 and 540J...looks like the 670 is a better deal...right?

Also how could the 840 warrant twice the price?

Intel Pentium Extreme Edition 840
64 bit Support: Yes
Cooling Device: Heatsink and Fan
Hyper-Threading Support: Yes
L1 Cache: 12KB+16KB
L2 Cache: 2 x 1MB
Multimedia Instruction: MMX, SSE, SSE2, SSE3
Operating Frequency: 3.2GHz
Process Type: 90 nm
Series: Pentium Extreme Edition
Voltage: 1.25-1.388V
Price= $1,066


Intel Pentium 4 670
64 bit Support: Yes
Cooling Device: Heatsink and Fan
Hyper-Threading Support: Yes
L1 Cache: 12KB+16KB
L2 Cache: 2MB
Multimedia Instruction: MMX, SSE, SSE2, SSE3
Operating Frequency: 3.8GHz
Process Type: 90 nm
Series: Pentium 4
Voltage: 1.25-1.388V
Price=$637.00


Intel Pentium 4 570J
64 bit Support: No
Cooling Device: Heatsink and Fan
Hyper-Threading Support: Yes
L1 Cache: 12KB+16KB
L2 Cache: 1MB
Multimedia Instruction: MMX, SSE, SSE2, SSE3
Operating Frequency: 3.8GHz
Process Type: 90 nm
Series: Pentium 4
Voltage: 1.525/1.53V
Price=$630.00

Answer : Problem: CPU for 955X chipset

The 670 and the 570J are pretty close in performance, with the 670 providing twice the L2 cache: http://www.xbitlabs.com/articles/cpu/display/pentium4-670_5.html  The extra cache doesn't make it significantly faster, but if it's only $7 more, it is a better pick.  Additionally, the 670 has EMT64 extensions which enable it to run 64-bit operations, which I don't think the 570J can do, while maintaining compatability with 32-bit OS'es.

The 840 is dual core, as well as hyperthreading, so that is the reason for the higher price.