NVMe Choice: 2TB PCIe 3.0, or 1TB PCIe 4.0?

Spec'ing out a new rig to do Resolve Studio editing (+ other tasks).
Wondering how much each NVMe metric matters for the Resolve cache drive: IOPS, size, TBW (ie longevity), etc. OS will be on its own separate NVMe.

I'm new to DR, but have done Premiere in the past. Reading/searching as much as I can, but have not found anything that answers this (esp. IOPS).

If you had to choose (due to budget) only between these 2 NVMe drives dedicated to cache, would you choose:
1) a *2*TB at ~3,500MBs read/3,000 MBs write and ~500K IOPS
- or -
2) a *1*TB at ~7,000MBs read/5,000MBs write and 700-900+K IOPS?

Part of the question is understanding how much IOPS and raw speeds affect DR, and how much thrashing is done on the cache (i.e. longevity). If 500K IOPS and 3,500MB/s is way beyond what DR will ever need, I'd rather opt for the slower 2TB. If I need more pure, raw speed, I'll go for the 1TB speed demon (yes, the MOBO and CPU are PCIe 4.0), and replace in a couple of years with bigger/better/faster/cheaper.

I'm doing mostly HD, moving into 4K, < 60 minutes, mp4 (h264 & h265), advanced home user (i.e. no professional delivery) - and care most about scrubbing performance.

Thoughts?

Thanks in advance!

I won't claim to have enough knowledge of Resolve to answer your question, but I have more experience with hardware so I just want to give a word of advice about specs.

There's a big difference between what the bus itself (PCIe 3.0 vs 4.0) is capable of and what the actual drive you purchase is capable of. As an example, for many years hard drives were prominently labelled as "SATA 3.0 600 MByte/sec", even though no hard drive can get anywhere near that speed - the physical platters just don't spin that fast. To use an analogy, just because you ride your bicycle on the freeway don't expect it to go 60MPH.

So be very careful to research the products you're interested in. If the PCIe 4.0 device can't actually perform any faster than the PCIe 3.0 device, then the fact that it can use a faster bus protocol is basically irrelevant and you can remove that variable from consideration.

Sean -
Thanks - I should have removed the bus spec from my post, as that confused the question. I stated specific drive performance numbers for the 2 choices for a reason - the NVMe drives' buses didn't actually matter in my post, only their speeds (my MOBO & CPU are both PCIe 4.0).

For those who aren't aware: just the type of bus interface doesn't define the speed of the drive. So you could potentially have a cheap "PCIe 4.0" NVMe drive that's *slower* than a good "PCIe 3.0" drive. Also, if you put a PCIe 4.0 NVMe on a PCIe 3.0 Motherboard (or CPU), it would be limited to PCIe 3.0 speeds, or ~3,500MBs (i.e. it would be a waste to get the PCIe 4.0 NVMe).


To reiterate: in my case, I'm talking about a choice between 2 specific options, both on a PCIe 4.0 MOBO. If you could *only* choose between the following:
1) a 2TB rated at ~3,500MBs read/3,000 MBs write and ~500K IOPS
- or -
2) a 1TB rated at ~7,000MBs read/5,000MBs write and 700-900+K IOPS?

Which would you choose, and why?