Help specing a PS machine

[Doc_Pit]

I work with very large files (sometimes 20GB-30GB). The primary problem I encounter is lag when I'm using the brush or clone stamp.  Having tried a number of fixes, I'm contemplating a new PC.   I've been communicating with Puget Systems.  I would like to know whether there is agreement with these two statements:

Our testing of Photoshop showed it is mainly a single-threaded program. So instead of benefiting from several CPU cores, mainly benefits from a high CPU frequency (GHz rating). That makes the 8-core Core i9 9900K with its 5.0GHz Max Turbo ideal.

For graphics card, there isn't much additional performance going above the RTX 2070 Super, so typically there is no need to do so.

I'd also be interested in knowing whether anyone has had particularly good or bad experiences with any specific vendor.  Thanks.

[Silkrooster]

Here is a link to photoshop specs.

https://helpx.adobe.com/photoshop/system-requirements.html

Frankly I am not sure if photoshop can use mutiple cores. Some computers will balance the cores to ease the load of the main core. Not all will though. Nor am I current on the latest technology.

As far as the graphics card. Only certain features of photoshop use the gpu, therefore speed is not as important as the amount of memory, drive space and speed of the cpu. 
The more memory on the gpu can help when using those features that support the gpu.

Use the specs as a starting point and add as much memory and drive space you can afford. Other than that, you should be fine.

One more thing when dealing with a file keep in mind the file size can be and more likely is compressed and will be larger when loaded into photoshop. 

Good luck...

[D Fosse · Accepted solution]

I don't know where this notion comes from that Photoshop is single-threaded. All you need to do is open task manager and you'll see the load spread over available cores. It's true that some tasks need to be performed in sequence, but that's due to the nature of the task itself, not Photoshop. That's the old joke about two women giving birth to a baby in 4.5 months.

But anyway that largely misses the point. Photoshop is generally not CPU-limited, but bandwidth-limited. What you're waiting for is moving large amounts of data through the memory subsystem. The crucial component is the scratch disk. That's where most of the action is.

What you need is a fast drive with lots of space set up as scratch disk. Traditionally that has been the bottleneck. There is no such thing as "enough" RAM, no matter how much you have! The scratch disk will always be used. Think of RAM as a fast-access cache to the scratch disk's main memory.

With the new ultra-fast NVMe drives (aka PCIe M.2), the need for huge amounts of RAM has diminished. RAM is probably still faster, but the difference has dropped to practically insignificant. It's a whole other story than spinning hard drives.

The main requirement of the GPU in Photoshop is reliability. Video driver bugs is a huge problem. They happen because drivers are mainly released to satisfy the gamers and let them run the latest games. The gaming community is generally not too preoccupied with correct protocol - so this tends to introduce bugs elsewhere. So they put band-aid on it and fix the bugs much later.

GeForces and standard Radeons are gaming cards. It might pay off to get a Quadro or a Radeon Pro. These cards are optimized for graphics, 3D and CAD, not games.

[Doc_Pit]

D, thanks a lot.  This comment, in particular, clarified my thinking: With the new ultra-fast NVMe drives (aka PCIe M.2), the need for huge amounts of RAM has diminished. RAM is probably still faster, but the difference has dropped to practically insignificant.   I'm considering a U.2 Intel® Optane™ SSD 905P 960GB Solid State Drive as a scratch drive.  I'm also going with a Quadro RTX 5000.  The stability is worth it to me.  As always, many thanks.

[D Fosse]

OK, that's interesting. This is an SSD that plugs into the PCIe ports on the motherboard. I was actually thinking of the new M.2 interface, which has its own ports on new motherboards. The M.2 form factor is much physically smaller - and a lot less expensive for the same nominal speeds and capacity. On good motherboards the M.2 ports will have a heatsink.

Do some more research on this before committing, especially on real-life transfer speeds. You may be able to save some money here if you're building this from scratch.

On the other hand, if you have room for a Quadro RTX 5000 on your budget, money is probably not a concern for you...;-)