@coughlin47 from a search it appears the PureRaw uses DeepPrime and there appears to be talk of DeepPrime XD being added? I use PhotoLab Elite so my experience is based upon that and have just upgraded from a GTX 1050 2MB to a RTX 3060 (retaining a 1050Ti on my other machine).
Before making that jump I tested some images on my Grandsons RTX 2060 in a Ryzen 3600X and my Son’s RTX 2080 in a Ryzen 3950X (possibly Ti but I am not sure) and put some test results here Which graphics card do you use with Photolab? - #27 by BHAYT and in other later posts.
The RTX 3080 should be a “beast” given the performance from my Son’s machine. However, there needs to be a balance between the graphics power for DP (and DP XD) and the processor power for the rest of the editing process and for feeding the graphics card which then does the “heavy lifting” for the Noise reduction.
I don’t now what prices the systems you are looking at are but given that a RTX 3080 sells for about £750 then providing there is enough in the budget to buy a reasonably powerful processor then you could either go for the 3080 or drop down a little and increase the power of the CPU, it really depends on how complex the editing of the images is.
If you run a test where you retain all the edits but remove the Noise reduction and then compare to the same test but with NR enabled you should be able to determine what proportion of the elapsed time is currently being spent in the two phases.
Although 5 years old the graphics card has 8GB memory so it might not be doing some useful work currently and you need to assess if your current processing approaches mine when the results from the other two machines and graphics cards might help determine which is the best route to reduce the 40 seconds to a more cost effective length.
In my tests the time for my 10 images was 6.6 times faster using my Grandson’s machine (than mine) and 9.8 times faster on my Son’s machine and the power and cost of one of those machines is very high, i.e. the graphics card cost of one probably exceeded the entire build cost of the other but that is not reflected in the performance difference.
There are processors faster than my Son’s machine but … and the 3080 should be faster still than his 2080(Ti?).
Your RAW images are over twice the size of mine so that is going to have an impact as well. Looking at the figures for my images the slower machine was processing each image in 6.6 seconds and the faster at 4.5 for DP XD. Doubling those times gives us at least 13.2 and 9 seconds per image or 1.1 hours and 45 minutes to process 300 images but I am outputting 100% JPGs in my tests and you are outputting DNGs and you may well have way more complex edits to apply.
I hope that this helps a bit.
Regards
Bryan