gtx 1060 3gb version
I'm looking into getting the gtx 1060 with  3gb of  vram  (single fan)

what i was wondering is:

Does it run with the most current version of hashcat (v4.2.1)?

Does it run well?

           for example would i have to add  --force to the command line?

And if anyone has one; could you give me a benchmark of it please?

i would like to use ubuntu 18.04 or 16.04 (18.04 preferred) with hashcat v4.2.1
All cards supported by current NVIDIA drivers will work with hashcat. You shouldn't have to use --force (at least, not at this writing. Someday you may have to. The 9xx, 10xx, and 20xx series should all be well supported.

I don't have a 1060 so I can't get you current (4.2.x) benchmarks for hashcat, but you can find some older ones around:
Thank you for the quick reply!

would the difference in vram (3gb instead of 6gb) cause the amount of hash/s to be significantly less?

the specs of the 1060 (with 6gb of vram) are:

6GB 192-Bit GDDR5
Core Clock 1506 MHz
Boost Clock 1708 MHz
1280 CUDA Cores

and the specs of the 1060 (with 3gb  of vram) are:

3GB 192-Bit GDDR5
Core Clock 1506 MHz
Boost Clock 1708 MHz
1152 CUDA Cores

or should i expect about the same results?
More VRAM is good for when you are trying large lists of hashes, or large combos of wordlists+rules, etc.

Note also that due to what I believe to be an error in NVIDIA's interpretation of the OpenCL spec:

... only 25% of that card's VRAM will be available for most attacks.

So I'd always go for more VRAM if you have the option.
the over all concern with the vram is; my motherboard only has 32gb of ddr4 ram
The plan is to have about 10 of these gpus totalling at 30gb vram

From what i’ve been told you need to have the total vram less than or equil to the ram on the motherboard for hashcat to run correctly

So even tho im only using 25% of the vram per card would the sum of the 10 cards vram compensate when using wordlists+rules etc?
I think that should be fine - it's not a hard requirement. You're close enough to it to be OK.
Thank you for the help!