Question 5950x - inefficient processor use

[BristolJGM]

Has anyone has this problem with the 5950x or other Ryzen processors?

I am using it for a heavy multi-threaded workload on Excel and sometimes find use like the attached picture. Task Manager shows about 60% CPU use. The processor appears to be very temperamental about when it does this, and how badly (no doubt there is some kind of underlying logic to it, but I don't know what).

I have tried this with SMT both enabled and disabled and get the same result.

See:

 

[SamirD]

Seems normal to me if you're pounding it. How much memory are you using?

 

[hotaru.hino]

Whatever you're crunching may just be hitting the wall of diminishing returns. This is especially true if what's being worked on has a lot of conditionals.

If you want to verify that multithreading is working as intended, run something like Cinebench.

 

[dorsai]

I would guess that Excel can only push the processor so far...frankly I am surprised you can even get to 60% with Excel I would have expected more like 6%

 

[BristolJGM]

I'm using several workbooks at once. With one or two large workbooks it can push it to 100% but it starts dropping after that, irrespective of whether they are linked to each other or not. Exactly how the workbook is written affects how much processor use there is - there can be a significant difference between two different ways of doing the same thing. I've tried asking on Excel forums without much luck - looks like it is a question of how best to create the workbooks - will try again there. Thanks for the responses!

 

[hotaru.hino]

Microsoft Office apps also employ reliability measures so you don't lose unsaved data if the app crashes. That can interfere with how efficiently you can use it to do compute workloads.

 

[BristolJGM]

Good call and I had Autosave off but Autorecover on - turned it off now. But this isn't it. Maybe it is just the limits of Excel. Very puzzling programme in that tiny differences to the spreadsheet (doing the exact same thing in two different ways) produce huge amounts of CPU usage differences.

 

[sizzling]

I'm using several workbooks at once. With one or two large workbooks it can push it to 100% but it starts dropping after that, irrespective of whether they are linked to each other or not. Exactly how the workbook is written affects how much processor use there is - there can be a significant difference between two different ways of doing the same thing. I've tried asking on Excel forums without much luck - looks like it is a question of how best to create the workbooks - will try again there. Thanks for the responses!

I have found the same that depending what formula you use dictates how many cpu threads will be used. What I have also found in RAM can be an issue. I’m running a 3700x with 32gb RAM. I found when using 16gb Excel would start heavily caching to the main drive when RAM was hitting about 70% usage. This significantly slowed things down, going to 32gb was a massive boost by avoiding the caching to main drive. My work has not hit similar 70% of 32gb so not sure what would happen. The 70% is from memory but it was somewhere around that number, nowhere near 100%.

 

[BristolJGM]

Mine isn't RAM related. I have 64GB and not getting close to using all of it.

It is a complex spreadsheet with lots of AVERAGIFs and INDEX/MATCH entries. I can run up to four similar workbooks at once with 100% CPU when solving but after that it goes downhill. This is the case even when they are independent so I don't think it's an issue with inefficient multi-threading (?)

With the "wrong" formulas, even if they are very similar, it goes downhill with over two workbooks open.

The slowdown appears to be related to how many workbooks are open, not the size of them. So 2 workbooks will run at 100% CPU even if they are enormous.

I've tried merging workbooks into a single one but that just causes an even worse slowdown.