Huge slowdown when rendering MR or Vray


It’s not a Windows issue outright, it’s a priority issue. If you have mental ray set to use all available cores/resources, it’s doing its best to do just that. You can set the Affinity for an application to use fewer cores as opposed to lowering the priority in TaskMan, for example. I’m still using Win7 myself (no plans to change that) and I have no issues with

It’s a Windows issue. My 4-core OS X laptop can render with Maya and comp in Nuke comfortably at the same time without dropping priorities. But my HP Z820 can’t do the same in Windows – that’s why it’s running Linux.

CGBeige has a massive bias against Windows and never really took the time to learn it, thus his sardonic remarks. Of course, you could spend thousands of dollars and try his "solution".

My gaming rig runs Windows 7 and I’m plenty familiar with Windows, from NT 4 all the way up to 7 and I review Windows VMs for Ars Technica, so get your bullshit straight:

And Linux is free, so the solution won’t cost anything if you want an OS that can multitask properly.


I use to have a HP Z820 workstation at work and i`m pretty sure it did a decent job of multi tasking whilst rendering in maya.

Think i`ll post a video on you tube to show what I mean.


Heres a video of the slowdowns.

Just rendering with mental ray in the background and using paint to show the problem. You`ll see me trying to move the window around and then drawing it occasionally freezes.
Now I agree I can reduce the cores that maya is using but I dont remember it ever being this bad.



don’t reduce your core usage. That’s just the worst idea I’ve ever heard to force your OS to multitask properly when rendering. Just drop the priority.


Thanks. Im trying ProLasso which seems to be doing the job, but I still think there is an underlying issue with my PC as ive never had to use something like this before. But at least it saves me having to keep manually reducing the priorities.


don’t reduce your core usage. That’s just the worst idea I’ve ever heard to force your OS to multitask properly when rendering. Just drop the priority.

The purpose of this thread wasn’t to start a flame war, CGBeige. You brought the “use a Mac” argument to the table - completely unnecessary and irrelevant to the issue here. It’d be amusing, if you weren’t so upset about it.

And given that you can’t even make Maya work properly in Windows, it’s obvious you lack the expertise you claim. If you’re happy with your Apple computers, excellent. So please stick to blogging about your extremely biased specialties and let the Windows users help, when it comes to Windows. You’re not helping at all here, just being argumentative and inflammatory once again.

@paulruk: It certainly seems like a driver issue, perhaps with your motherboard chipset drivers? I doubt it’s the GPU drivers, but with your Photoshop issues that may play a part. Which graphics card are you using?

I’m experiencing excellent speed gains, 10% or more, when using ProcessLasso to manage threading vs. Windows alone. I can’t recommend it enough. Responsiveness remains at 100% while rendering in mental ray, Photoshopping, and Rhinoing all at once. I’m generally using 5 cores for Maya and one for everything else (Phenom X6 1100T here), with dynamic boosts of course helping things along for CPU speed. With 6 cores rendering, responsiveness remains at 100% too though, until I start tossing other applications into play.


Thanks Im using an Nvida gtx 465 but dont think its that, Ive been trying various chipset drivers and not having much luck. Im using a Asus P8P67 Pro motherboard, 16gb 1600mhz ram, 128gb SSd and tried various versions of chipset drivers but nothing changes. Had it for a few years now and I recall having similar issues about a year ago and a windows re-install fixed it. Getting close to just upgrading the motherboard to a newer chipset to see if that helps. I have some other issues like slower ssd benchmarks speed than normal and the very occasional black or corrupt screen (couple of times a month). So Im just thinking of trying a new motherboard.


Linux and OSX handle threading better in general. That’s just a fact. You don’t need to manually set priorities in them (though you can, and sometimes should), because it assumes whatever you’re doing in the foreground gets priority.

Windows has always needed to have threads manually set lower to not interfere with foreground tasks.

I’ve noticed over the years as processors get more cores and memory gets more latency, that windows doesn’t handle low priority jobs quite like it used to and they interfere more with foreground tasks. I’ve started restricting the number of cores, leaving 2 available for foreground tasks during the day, then use them all when I’ve left for the day.

The lag isn’t always horrible if I have a background task set to use all cores/threads, but in some cases the computer is barely usable.

It gets confusing with hyperthreading. I don’t count virtual cores as real cores, so on my 6-core/12 thread 3930k i7, I use 4 cores (4 threads total) during the day for background tasks so I have 2 real cores available, and when I leave I set it to use all 6 cores/12 threads. This is because if I set the background task to use 10 threads, it’ll use all 6 cores, plus 4 hyperthreads, leaving me without any dedicated cores for foreground tasks.


Are the slowdowns as bad as this though?
i`ve never had it as slow as this, when you literately have to press ctrl+alt del to get the task manager up to regain mouse control?


@paulruk: I highly recommend the Asus Sabertooth motherboards, if that’s an option for you. Using the 990FX for both my Phenom 1100T and the FX-8120, and they’re just wonderful and very feature-rich. You seem to know your salt so you likely don’t need a recommendation, but they’re working very well for me. I actually swapped in the 990FX on this Phenom after using one for awhile with the Bulldozer, and experienced some nice render-speed gains just switching to a better motherboard, here at work. Much better thermal control as well; the Thermal Radar software works flawlessly.

@Sentry66: Aye, it’s well-established. I imagine much of what ProcessLasso is doing is something built-in to those operating systems, as CGB and I have pointed out before. One shouldn’t need a third-party application to handle this stuff, but it also gives much more control and flexibility than any of the three OSs do out of the box, so it’s a winner. :wink:


yeah, slowdowns can be that bad if something is using all the cores. I’ve seen it about that bad in some cases with Windows even when a background task is set to low priority. It just depends on how the I/O is being taxed.

If anyone has ever run AIDA64 with it’s stress test that stresses CPU, memory, hard drive, FPU, GPU, and cache, even on a low priority running that will make the machine not very responsive.

However just running prime95 or something that just stresses CPU only without taxing your other I/O sub systems, things are almost 100% responsive when it’s set as a lower priority


mental ray seems to be worse than V-Ray in this regard so what you’re seeing is common with what I know of mental ray in Windows.


[QUOTE=InfernalDarkness]@paulruk: I highly recommend the Asus Sabertooth motherboards, if that’s an option for you.

Thanks, I have the Intel 2600k so would need something like the Intel Z77 chipset. I think im going to go with a cheaper gigabyte board which is half the cost of the Asus in the part of the world I live in. This was my first Asus board and to be honest im not that impressed, even though they are one of the better manufacturers out there. Once bitten twice shy I guess.


Thanks, Yes v-ray isnt too bad at all on my system, and you can adjust the threads and lower the priority in the settings. But Mental Ray just kills it, the ProLasso is saving my system now.


don’t buy a Gigabyte board. They make crap and I had to send two back because they just black out on boot and just fall apart in general. The ASRock mobo I have is good but I’d never buy another Gigabyte


hehe I`ve been having another discussion on another forum and I initially was going for an ASRock Z77 Pro 3 board which is similar price to that gigabyte but they were saying dont get ASRock they have poor quality control ie things breaking off them easily and arriving dead .
Never owned either board , always had asus, msi or supermicro but they both seem to get decent reviews.


Read the newegg reviews for the board you are looking to buy. I didn’t and tons of other people reported the same flakiness with Gigabyte. It’s not worth the cost savings IMO. The miser pays twice, as the saying goes


I was looking on there earlier actually funnily enough., But if you look at the ASrock motherboards some of the reviews are horrendous, many turning up DOA. For example the gigabyte board i`m looking at has 18% of reviews with only 1 or 2 ratings compared to 26% for the similar ASrock. So by that should I take it that more people are unhappy with ASRock than Gigabyte?
I just find user reviews can sometimes be more of a hindrance than helpful and often more people who have had problems write bad reviews out of frustration. Certainly if there is a significant problem with a product its helpful but on the whole everyones experiences are different I find.


I’m not saying ASRock is the best and obviously personal experience is to be taken with a grain of salt but there is a reason those Gigabyte boards are so cheap

When you’re on a deadline and you get a black screen at the BIOS and a CMOS reset does nothing, saving $100 doesn’t seem so smart


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