Xeon Processor Selection - How does Cache work?

[Phil]

Hi all

Looking at getting a HP G4 Workstation for Plant 3D (mainly) and some future Inventor work.

The last machine I bought had a W-2135 processor which has 8.25Mb cache and 6 cores.  It runs at 3.7GHz, turbos to 4.5GHz.  This appears to be the fastest Xeon processor available in pure clock speed.

Looking at the W-2145, this has the same speed rating but with 11Mb cache and 8 cores.

Both therefore have 1.375Mb per processor core.

Is this how cache actually works?  Is a specific amount allocated/fixed to each processor core, or is the total available cache memory available to whichever cores are loaded?

If the former is correct, I would expect the two processors to behave the same when running AutoCAD based apps.  If the latter is true, there may be some advantage in specifying the W-2145 for the new machine.

Comments appreciated.

Phil

[pendean]

Good read here https://www.maketecheasier.com/how-cpu-cache-work/

[Phil]

Thanks Pendean

But that article doesn't actually answer the question raised.

I am interested to know whether 8.25Mb cache memory on a 6 core processor is pre-allocated/fixed at 1.375Mb per core, or whether each operational core can grab all available cache memory.

Phil

[pendean · Accepted solution]

You'll need to visit chip maker websites and forums for that level of information.

[Phil]

Thanks Pendean, I will give that a try.

Phil

[dgorsman]

Like "turbo" mode clock speed and other features, unless you're writing very low level code (highly unlikely these days) these can be safely ignored.  Just look at number of cores and clock speed.