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Processor bottleneck

P3nT4gR4m
Consultant
So I have 32 gigs of ram and a GTX 1080 tooling away under the hood but lately my core-i5 is proving to be the weak link in the chain. Once I'm north of around 20 gigs of sdf data I get an attack of the laggychops and a perfmon quickly shows that my cheap and nasty cpu is hitting 100% whilst the rest of my box is barely breaking a sweat.

However, upgrading to an i7 is going to set me back around half a grand so, before I drop that kind of dosh I'd like a good idea of how much difference this is going to make in real terms. I'd be especially interested in hearing from anyone who has 32 gigs and an i7 and ultra interested in anyone who's upgraded from i5 because of lag?

The way I see it there's two possibilities - either I slap in an i7 and all my woes melt away or I shell out 500 quid and get barely any discernible improvement in performance and then all sorts of broken stuff starts appearing round my house and fist shaped holes appear in doors and walls and whatnot.
14 REPLIES 14

P3nT4gR4m
Consultant
Cheers guys, I think I'ma stick with where I am at the moment. Same as @DeadlyJoe - framerate drop is noticeable but definitely not unusable. Pretty confident that it's the CPU end, tho as it's at it's most annoying when I'm fine lining at max res and it seems to take a while for the stroke I'm doing to make it to the screen and the step effect gets really pronounced. I can get around it by taking my time and doing real slow strokes which, although it's much slower than my usual manic scribbling probably leads to a cleaner, more deliberate sculpt at the end of the day.

Also in the back of my mind is bus bandwidth which I haven't checked yet and will have to investigate thoroughly before I commit to that kind of spend, especially considering I'm just about to drop the same on some meatspace sculpting classes. Damn you Medium team - for free software you sure are turning into a right f'kin money pit 😄

@MattHickman What would really save the day is if we could paint on bumpmaps since I guess I'm getting down to detail levels now that really have no business being handled by geometry.

DeadlyJoe
Rising Star

P3nT4gR4m said:


@MattHickman What would really save the day is if we could paint on bumpmaps since I guess I'm getting down to detail levels now that really have no business being handled by geometry.



+1
I really hope that's in the plan for the next update or two.

cleanupdisc
Adventurer

DeadlyJoe said:

I'm still using my old i7 4790k with a GTX 980Ti and I don't experience any severe hiccups when Medium exceeds 20GB (out of 32GB DDR3-1600 installed). Churning that much geometry does definitely drop the frame rate, but not to the point where it's unusable.


 
The i7 4790k is a beast. Im still using it at stock settings and it destroys anything fed to it.

nosferalatu
Protege
 Pretty confident that it's the CPU end, tho as it's at it's most annoying when I'm fine lining at max res
> and it seems to take a while for the stroke I'm doing to make it to the screen and the step effect
> gets really pronounced

Yep, that sounds exactly like the CPU is the bottleneck. Matt H described it well in an earlier post, but I just wanted to chime in and say that what you're describing sounds like you're being limited by the CPU. Medium's sculpting operations use the CPU, not the GPU, and use all available threads to do that sculpting work. If you move your hand in Medium, but the clay sculpting doesn't keep up, that's because the CPU can't keep up.

Also note that we use AVX2 when it's available, and fall back to SSE4 if not, so a CPU that supports AVX2 is best (only older ones lack AVX2 support; not sure where your i5 lands). That primarily affects stamps and the move tool.

We do stream a lot of data to the GPU across the PCI bus, so it's worth checking that your bus isn't set to 1x mode or something like that, but what you're describing sounds like a CPU issue.


Anonymous
Not applicable
Interesting. Don't have an answer for you, but I have 32gigs, a 1080 FE and an AMD FX(tm) 8350 Eight core, 4000Mhz cpu -- (CPU benchmarks in the lower i7 range), and frequently hit bottlenecks . Wouldn't be surprised if the choke point is something else, or simply the result of pushing the detail up to levels that the machines can't handle yet.  If I had a supercomputer I'd probably be trying to work at 40-50 levels of resolution, or trying to work in a coliseum sized work area,  since I have a natural tendency to push as far as I can with things like that... 

Also not really sure what else pulls cpu, I'm getting a fairly large stamp, model, and image library built up, not sure how much of that is actively stored while working.  Have noticed fairly significant delays after a video/photo is completed, so I'm guessing those are writing to the hard drive (no ssd yet) or there is a hit when it builds the notification (which I have disabled, but its logging them in the main windows)