Hi There!
SC II is the only game that I play on my pc. I am not interested in other game, I have a huge passion for SCII.
I would like to ask you a suggestion for a good graphic unit. As I said, the GPU would be used only for playing scII. I want to play with high fps (currently: 40)
My budget is limited: I can spend about 150 €
my config:
intel I3 7100 3.90 ghz
8gb ram
for now: nvidia geforce GTS450
other question: I have a motherboard asus model H170M-E D3: should I check if the future gpu fits for my mb or is a model common for every gpu?
Thank you for your tips guys, it will be very usefull to me
most motherboards is forwards compatible with modern gpus. to prove it i will tell you this: my motherboard with an intel core 2 duo cpu could run a 900 series gpu without issues. the only exeption is oem motherboards. not that i think that your is an oem motherboard, just saying how the difference is. as for a gpu capable of running starcraft 2 well: that is tricky. i struggled with both gtx 1070 and 1080 and 1080 ti. it was only when i upgraded to rtx 2080 ti that it worked well. that does not mean that you need a 2080 ti but, you do need an RTX gpu or maybe a gtx 1650 or 1660 ti. i do not know as i have not tested them. you do need more ram however, as the game runs out of memory pretty fast when i only have 8 gigabytes. it might be enough with dedicated graphics memory however but i am not sure. sorry about a long post. i am going to stick around. if something is unclear, just tell me and i will try to clear it up for you.
All modern Gpus use the same port, so you don’t have to worry about compatibility.
Get something like a 1050 ti or 1060 gpu, anything more than that will be overkill (an RTX card is completely pointless for SC2), especially if you don’t upgrade the cpu, Sc2 is generally more demanding on cpu than gpu.
Since you are on a budget, I would try to get it used. Might only use half your budget that way if you find a good deal. 
A used 960 or 970, would also be perfectly fine and more than twice as fast as your current card.
I think your cpu is fine, it’s only 2 cores, but Sc2 can’t take advantage of more than, and 7100 has a pretty decent clock speed, 8 GB ram is plenty.
The only significant improvement you can achieve with your current motherboard cpu-wise, is to get a sixth or seventh gen K cpu, and then overclock it.
thank you very much guys for your answer! I appraciate it 
I saw on amazon the model you mentioned (1050 ti or 1060) and for some model I am on budget. My current gpu is 10 years old, and it is time to change it. For this reason, I choose to improve this component instead of the others.
Do you think that with a change like this in my current config I could improve the performance in game?
In sc2, as you know, it crucial to have a fluent experience in game. I know that SC2 is cpu demanding, but if I can choose, I prefer to update the gpu for the moment.
Yes, since your current gpu is so old it’s a bit of a bottleneck, I expect pretty stable 60 fps shouldn’t be a problem if you get a 1050 ti.
A 1060 might give you more stable fps at ultra settings, but if you don’t care about having all the settings at max, either would be fine.
If you experience fps drops after the upgrade, it’s more likely it’s the cpu that’s to blame.
i had bad framerate on gtx 1080 and 1070. 1080 ti was also not optimal. 8 gigabytes of ram is not enough, because you need memory to run both the game and the system. 12 might be enough but, 16 will be enough. with a quad core cpu, you can use 2 cores to run background tasks and the rest to run the game.
That’s BS, if you had bad framerate it wasn’t because of the GPU or ram. Don’t give him bad advice.
Either you had a too slow cpu, or you were running too many background tasks. Maybe you were running the 64 bit SC2 launcher, it can sometimes be less stable than the 32 bit one. It could also have been a graphics driver problem
And he’s on a budget that wouldn’t have room for anything more expensive anyway.
If he wanted to spend more money it should be on a faster cpu, not more ram or a better gpu than the ones I’ve already suggested. It would be a waste of money.
A question. Any advice is greatly appreciated. Will SC2 (and WoW) play good at ultra settings with a RTX 2060 (6G DDR6 dedicated), 16G ram and a 9th gen Intel i7 and a 1TB SSD? Do you think this setup would suffer from low frame rates? Panel is FHD at 144hz with gsync Thanks again I really appreciate it!
world of warcraft yes, that works well even on a gtx 770m. starcraft 2? that is likely. i have not however tested it on that gpu but, i think it should work.