Excel not runnning all cores at 100%

Reubenb04 · 26 May 2011

Hi all,

I run alot excel & visual basic simulations that normally take about 4-7hrs to calculate. i've noticed through task manager(performance) that all 4 cores are running but only 1 core is running at 90% and the other 3 running at about 60%.

Is it possible to have all 4 cores running at 100% My hope is that all cores maxmised will slash the proccessing time by atleast 20%.

Any help will be much appreciated.

my system:-
-Windows 7 Ultimate 64bit.
-Intel Q9650(3Ghz) overclocked to 3.5Ghz
-Gigabyte GA-P35-DS3
-4gb DDR2 800Mhz
-250gb WD Cavier Blue
-Freezer Pro rev2

HammerHead · 26 May 2011

Would a ram disk be of help? I know that doesn't solve the cpu core issue.

Reubenb04 · 26 May 2011

HammerHead said:

Would a ram disk be of help? I know that doesn't solve the cpu core issue.

Thanks Hammerhead, what is a ram disk.

HammerHead · 26 May 2011

This can explain it better than I can.

RAM disk - Wikipedia, the free encyclopedia

There is software available to set up ram disks, some of it is free. IMO if you are not ram starved you might as well put it to work.

Reubenb04 · 26 May 2011

Thanks, will try that and see how much diiferent the performance will be.

Golden · 26 May 2011

Hi Reuben,

Unfortunately, I suspect the thread loading is controlled by the application - in your case Excel, so there may not be much you can do about it.

I have similar issues with a different set of software running, ironically also simulations, but using geological and mine planning software. I have used this counter-intuitive? technique to squeeze a little bit more out of the active CPU threads, but the gain is really quite minimal, but there is at least a little gain. With the software I use, the simulations are more RAM intensive, so I split my work into multiple copies and run several instances of the simulation since I have 24GB of RAM I can utilise, but I also try to maximise the CPU usage.

The trick in my case is to avoid spreading the work across all the cores if they aren't being used fully. For example, I only allow the executable to utilise for example core 1,2 and 3. That way, there isn't any overhead lost when the work swaps between cores as it requires, if that makes sense.

Try this:

1. Open Task Manager, under the Processes tab, find EXCEL.EXE *32 (assuming your are using 32 bit Office)
2. Right-click on EXCEL.EXE *32 and then select Set Affinity
3. By default <All Processors> will be ticked - try limiting Excel to only use 3 threads only, and see if that works for you.

As I said, it worked for me with some processes I run, but not all of them, so it may not work for Excel.

Let us know how you get on.

Regards,
Golden

Reubenb04 · 26 May 2011

Many thanks Golden, am currently running a simulation using Ram Disk. Still only one core is at 94% and the other 3 about 64%. Normal time is always about 7hrs and hoping to hit about 5hrs(an opportunistic 20% reduction in processing time with ram disk). Will definitely try your method afterwards.

cheers.

DarkXeno · 26 May 2011

This all depends on what version of excel I believe that most office apps are built with a single core in mind to be able to work with older machines, your best bet is to set excel to one core VB to another core giving them full access to them and then leaving the other two cores for windows task so it doesnt lock up.