Since recently Iray makes my PC lag badly [solved]

enbismain

I had break from active DAZ usage since this winter, and in that time I upgraded my Windows 10 to 11, updaged some drivers and just today got my hands to updating DAZ to current 4.20.0.17 version. From what - not sure, but 4.something.

Now, Iray preview has been a bit laggy before, but it never was THIS bad. Currently the preview is just unusable and render likely won't finish in eternity (I didn't attempt waiting it for long, so not sure). Even empty scene with a lone white cube gives 100% load of everything - even cursor lags badly, takes a while to click on dropdown menu to disable it. It used to be bad only on some heavy long hair/fur renders on exactly same PC. Nothing has changed about it other than Windows and DAZ updates.

Any idea what could be the problem and how to fix it?

Attaching fresh log from a few seconds of laggy iray preview.

AMD Ryzen 5 2600X 3.60 GHz, 16 GB RAM, GeForce GTX 1060 6GB driver 512.95, Windows 11 Pro 21H2

Sevrin

Do you have CPU rendering enabled there?  Best practice when you have an Iray-compatible GPU available is to disable CPU rendering.

enbismain

Sevrin said:

Do you have CPU rendering enabled there?  Best practice when you have an Iray-compatible GPU available is to disable CPU rendering.

Oh, thanks! It was, indeed, turned on - even though I'm very much sure I've disabled it couple years ago when I first discovered DAZ. No idea how it could've get back on, I surely didn't do it, so maybe it was somehow reset to default when updating or something. Anyway, seems better now. 

Just to be sure: is this the correct way to disable it? The CPU checkboxes were checked, I unchecked them. Any other ones I better un/check there?

Sevrin

No, that will do it.  

Near the bottom there's an "Allow CPU fallback" option.  I prefer to uncheck that, as well.  I'd rather take action to reduce memory consumption of a scene than do a final render on CPU.