Sim racing and refresh rates

vcl_X1 · 5 Jun 2020 at 14:36

Hi all,

I'm pretty certain the move from 60hz to 140-144hz and beyond is hugely beneficial for FPS but how relevant is it for Sim racing? Say Assetto Corsa and Iracing.

My conundrum is stick with 1440p monitors (and a rift) or go for the first new monitor as 4K but drop back to 60hz.

My preference is rarely to revert to a lower standard but there aren't any 4k monitors that I can find that don't have 60hz refresh.

V

YoungBlood · 5 Jun 2020 at 14:42

Have you considered ultra-wide monitors? Changes the game in racing.

3440x1440 @ 120hz over 4k @ 60hz any day of the week for me.
Higher than 60hz 4k exist but you need to pay handsomely for them, and you won't have the hardware to drive 4K @ 120hz anyway.

arknor · 5 Jun 2020 at 14:45

I doubt it's relevant because you know where you are driving in advance, you know exactly what line you want to take and if you can't recover from a slide I doubt an extra 1ms would help you.
also you are constantly sending inputs anyway your not really reacting to the screen like an FPS when suddenly a guy appears.
your always aware of whats happening

I'd think the FOV you use would have way more impact.

I think I remember using some 3rd party website to calculate what I should be using in iracing and it definitely helped

~>Dg<~ · 5 Jun 2020 at 15:14

high hz is a big help. it depends what you doing how much you push or expecting to progress to. also what game you playing. high hz is a big help in racing games.

vcl_X1 · 6 Jun 2020 at 19:19

Interesting thoughts, thank you. My FOV is sorted and easily updated if and when I need to change it

I do like the idea of one ~43 or 49 ultrawide but 3 or 4 32-34" would be fine too, I have had my 1440 monitors for quite a while so the logic is partly that I'll have them for say 5 years at least especially as vr improves too and I upgrade from the rift, the other hardware will improve over the monitors lifetime so open up upgrade possibilities rather than close them down, push everything else in my system right now to it's limits, I'm running a 1660ti atm so that's my weakest link right now, I intend to change this late this year/early next all the way to 3080ti or equivalent, I see no point buying a 2080ti now.

My crazy idea is 3 49's but that's complete overkill.

Guest2 · 6 Jun 2020 at 21:33

Something like these would be much better than 4k 60hz

https://www.overclockers.co.uk/asus-rog-strix-xg43vq-43-3840x1200-va-120hz-1ms-freesync-2-g-sync-compatible-hdr400-curved-ultrawid-mo-0am-as.html

https://www.overclockers.co.uk/lg-34gk950f-34-3440x1440-nano-ips-freesync-2-hdr-144hz-1ms-curved-widescreen-led-monitor-mo-14w-lg.html

vcl_X1 · 6 Jun 2020 at 21:43

Guest2 said:
Something like these would be much better than 4k 60hz

https://www.overclockers.co.uk/asus-rog-strix-xg43vq-43-3840x1200-va-120hz-1ms-freesync-2-g-sync-compatible-hdr400-curved-ultrawid-mo-0am-as.html

I excluded this one on the x 1200 resolution, weirdly between 1080 and 1440.

I'll have a think about the LG, thanks for the idea.

Guest2 · 6 Jun 2020 at 22:24

vcl_X1 said:
I excluded this one on the x 1200 resolution, weirdly between 1080 and 1440.

I'll have a think about the LG, thanks for the idea.

Oh yeh, that is a bit of a strange res.
Does 144hz, IPS, Gsync, 3440 x 1440 exist?

banja · 7 Jun 2020 at 00:35

Aside from the motion looking more fluid, it's all about input lag, which is very important in sim racing and is helped with higher refresh rates.

Just a basic example: With 60hz refresh (and at 60fps) your car - as calculated in the sim - is always at least 16.6ms ahead of what you're actually seeing. At 180kph you're moving at 50 meters per second. At that speed you're seeing your car on the track 0.83m behind where it really is. That may not seem like much, but with other processing and monitor response time this is certainly higher / further.

On a 144hz monitor (assuming you can reach 144fps) you are only 0.35m behind where you car actually is. It makes a difference. At 200 mph - say in an in F1 car - you're about 1.5 meters / 5ft behind your car at 60hz. Some people claim input lag doesn't effect them, but that's irrelevant, it's there regardless.

I'm unsure whether TN screens are still much more responsive than other monitor types these days. I have a TN 144hz gsync monitor (1080p) and the lag is extremely low. And the fluidity was a big improvement for me. At 60hz the peripheral images in sim (iRacing here mostly) seem to judder and stutter by. High refresh and gsync makes it buttery smooth.

MagicBoy · 7 Jun 2020 at 00:46

With iRacing the physics is on a 60Hz cycle, so any frame rate above that is just interpolated off the last set of data. I'm happy with anything over 60fps.

Given that you're racing people likely thousands of miles away with a 100ms latency at best via the internet, any gains from higher interpolated fps are likely zero.

banja · 7 Jun 2020 at 06:15

iRacing's physics engine runs at 360hz (at least) The FFB is 60hz though.

360 Hz, is the short answer. But we calculate forces twice per update step, so we do player tire force calculations at least 4x2x360 = 2880 times per second. More if some of the tires are contacting multiple surfaces (i.e. curbs).

vcl_X1 · 7 Jun 2020 at 11:20

[QUOTE="Does 144hz, IPS, Gsync, 3440 x 1440 exist?[/QUOTE]

It sure does, as does 3840 x 1600 144hz IPS Gsync There's an LG 38 that might just fit the bill, I just wonder how long before it arrives in stock, it's pre order at present

https://www.overclockers.co.uk/lg-3...een-led-backlit-curved-monitor-mo-15g-lg.html

MagicBoy · 7 Jun 2020 at 13:06

banja said:
iRacing's physics engine runs at 360hz (at least) The FFB is 60hz though.

360 Hz, is the short answer. But we calculate forces twice per update step, so we do player tire force calculations at least 4x2x360 = 2880 times per second. More if some of the tires are contacting multiple surfaces (i.e. curbs).

I'm aware of that, however in the context of this discussion it outputs every 16.6ms to the renderer. ie 60Hz. Physics and the renderer are decoupled.