[Jagerball]

As I'm sure is obvious, I'm in the middle of building a HTPC. My first. I've purchased the case (Digitalis HTPC) and mobo (Abit IS7-E) and am on to the CPU.


I'm looking at getting between 2.4GHz and 2.8GHz, depending on pricing. When browsing Ebay I see the above in 533FSB and 800FSB.


Am I correct in assuming that price being equal I should take a slower chip (say 2.4 over 2.6) if it has the higher FSB? Given that I can OC to about the same speed, the higher bus speed is more important, right?


Thanks.

 

[Morbius]

Quote:

Originally posted by Jagerball As I'm sure is obvious, I'm in the middle of building a HTPC. My first. I've purchased the case (Digitalis HTPC) and mobo (Abit IS7-E) and am on to the CPU. I'm looking at getting between 2.4GHz and 2.8GHz, depending on pricing. When browsing Ebay I see the above in 533FSB and 800FSB. Am I correct in assuming that price being equal I should take a slower chip (say 2.4 over 2.6) if it has the higher FSB? Given that I can OC to about the same speed, the higher bus speed is more important, right?

In general, the answer would depend on where the bottleneck is - whether you are compute bound or data bound.


If you are compute bound - that is not enough CPU horsepower for the task - then the faster processor would be better.


If you are data bound - that is you can't get data back and forth between memory and CPU fast enough - then the higher

data bus speed would help.


In an HTPC application, unless you are doing some fancy real-time processing, you aren't compute bound - so I'd go

with the faster data bus.


If you can overclock the chip on the faster bus, to equal the faster speed of a CPU on a slower bus - then you have

the best of both.

 

[Jagerball]

Thanks, that confirms what I was thinking.


Do you happen to work at LLL? I have a friend that works there.

 

[cowtown]

Generally you want the fastest FSB you can get. In the case of the 2.4 you should be able to get another 100-200MHz out of it with little trouble. With my 1.8 P4 I had I overclocked to 2.2 without anything but a change in the BIOS, no voltage increases or anything. So to re-iterate what Morbius said, get the slower chip with the faster FSB.

 

[pmerritt]

the p4 2.4ghzC(800Mhz) is known to easily overclock to at least 3Ghz

 

[e vey]

--In an HTPC application, unless you are doing some fancy real-time processing, you aren't compute bound - so I'd go

with the faster data bus.--



Hmmm. I am not sure that I know exactly what an HTPC is anymore, so choosing CPUs and FSBs based on un-named HTPC tasks makes me wonder where the bottleneck is for specific things.


Two or three years ago, an HTPC was a cheap scaler to play DVDs on. Compute or Data bound?


Then this group started putting TV tuners in and were worried about how to compress video faster. Compute or Data bound?


Then, people like me, began doing more "Capture and Compress on-the-fly" things, sometimes time shifting and sometimes recording straight to a highly compressed file like WMV and Divx. Compute or Data bound?


Then came MPEG2 compression on a chip. Uncompressing seemed to take more effort.


The lastest is the Fusion 2 which needs DXVA to uncompress unless you hapen to have a 2.4 or faster. What's the bottleneck there? Bus or CPU?


I am not being argumentative, I just want everybody to be on the same page.

 

[cowtown]

Everything can be affected by how fast the processor is in pure clock speed, however that said the faster you can get data of any type in and out of the CPU the better.


All I'm really saying is that the benefits of 200MHz in total CPU speed are easily mitigated by a 30% faster bus regardless of the task.