Same car, same setup, same track, 2 different PCs = different acceleration ?

[marcov7625]

Hello everyone.

I got a setup from a friend for Monza and when I tried it, I found out I was slower on the straight...
I checked both replays (friend lap and my lap) and I found out a significative difference in performance: 0.4 s to speed up from 210 kph to 260 kph.
Same car (Lambo 2019), same track, same condition, same setup.
And as I checked the acceleration on the straight, driver skills would not change the result...

The time was calculated watching the Racelogic display in the car.

I'm wondering how that is possible.
I did other checks at other speeds (e.g. 230-270 kmh) and the difference is still there...

Did you experience similar situation ?
Can 2 different PCs configuration change the performance of the car ?

Thank you in advance

 

[Majuh]

Maybe your throttle pedal doesn't output 100% throttle when fully pressed.

 

[marcov7625]

I was thinking that, but the throttle bar in the game is completely green for both.

 

[Jempy]

Did you compare during a same session as your friend ( practice or hotlap or qualification or even race ) ?

Not the same day of week maybe and not the perfectly same road grip might give different results for pure acceleration.
Moreover I'm not even sure that the ACC weather system might not even keep a slight amount of random in temperatures and grip on a same kind of session.

 

[Brushwood69]

sounds like you need a multiuser server drag race then compare motec

 

[Ho3n3r]

Did you compare during a same session as your friend ( practice or hotlap or qualification or even race ) ?

Not the same day of week maybe and not the perfectly same road grip might give different results for pure acceleration.
Moreover I'm not even sure that the ACC weather system might not even keep a slight amount of random in temperatures and grip on a same kind of session.

What he said - must be the same exact session for it to be a valid comparison.

You say same condition, were the temperatures exactly the same to the degree? Maybe he had a tailwind and you had a headwind.

 

[marcov7625]

I'm not aware he changed the wind. Basically we used same condition: sunny weather (the first option in the list) without modifying anything.

The test is done at high speed (from 210 to 260 kmh) in 4th-6th gear and with optimal grip. So traction control does not cut the power.

Tanks almost empty.

Basically I do it in 8.5 s.
He did it in 8.1 s.

With Lambo Huracan 2019.

I also did the same test with Lexus, with aero load at mimimum and it is slower than Lambo, but if you check videos on Youtube, you can find people doing it in 7.1 sec......just check the Racelogic display. That sounds impossible to me...

 

[Durge Driven]

No one answered the question

Yes 2 different PC hardware and configs could affect driver performance, more input lag etc.

 

[Gevatter]

Tanks almost empty.

I'm not aware he changed the wind.

You should control for that. Almost empty could be a few liters difference. I think the only session where you could be reasonably certain that all conditions are the same is a hotlap session. Everything else could have some sort of randomization built in to the track conditions.

The test is done at high speed (from 210 to 260 kmh) in 4th-6th gear and with optimal grip.

Are you aware if your test started at the same point on a given straight? For example, if you're slower out of parabolica than your friend, your'll reach the 210 later, wich means you'll run your test on a different part of the straight than your friend, which means there could be a slight uphill/downhill part or other quirks in the road surface. Shift timing also comes into play.

The time was calculated watching the Racelogic display in the car.

I'd rather watch the hud display. the dashboards in the car sometimes have weird graphical glitches or even a bit of lag, at least they had on my old system, probably depends on your graphics settings.

 

[marcov7625]

As far as I know, it is not possible to change or check the wind speed in ACC. How do you do that ?

What I measured is the time to go from 210 to 260 kmh, therefore from this speed to that speed on the same part of the circuit with sunny condition in hot lap mode. It does not matter the exact point, as I am not measuring the time to go from here to there, but from this speed to that speed.

I also checked from 220 to 260 s between the Ascari and the Parabolica. He can do it in 6.6 sec. I cannot do better than 7 sec...

If you check the hud or Motec, you get the same time of Racelogic. The difference is Racelogic does not show the cents of second, but I'm talking about almost half a second difference.

If you like, make the same test.

Choose a car, go to Monza in sunny condition, aggressive setup, aero load at minimum, Hot lap mode and do few laps. Then watch the replay and see what you did to go from 220 to 260 between the Ascari and the Parabolica.

My best is 7 sec and there is no driver skill here. We are on the straight line.

 

[marcov7625]

No one answered the question

Yes 2 different PC hardware and configs could affect driver performance, more input lag etc.

Thank you for confirming that.

 

[Gevatter]

What I measured is the time to go from 210 to 260 kmh, therefore from this speed to that speed on the same part of the circuit with sunny condition in hot lap mode. It does not matter the exact point, as I am not measuring the time to go from here to there, but from this speed to that speed.

Of course it does. If you hypothetically had to go a little further because you reached 210 later, the track could be different, slightly uphill for example. Do you not think your car would accelerate slower if it was going slightly uphill? I'm not saying this is the case here, I'm just saying if you cannot reproduce more or less exact start/end points of your measurements, a comparison is somewhat moot. There's also shifting involved between 210 and 260, so shift points are relevant.

What I'm saying is just because it's in a straight line, you can't take the driver out of the equation completely. The best test would be if your friend can do his times on your hardware.

 

[After_Midnight]

As far as I know, it is not possible check the wind speed in ACC. How do you do that ?

 

[Gevatter]

Here are my times I did. I had a spin at della Roggia in laps 1 and 8, so feel free to discount those if you feel those spins could influence the measured times.

Lamborghini Huracan 2019, Agressive Preset with no further changes; Monza 2019, Hotlap Mode, Optimum Grip, start time 08:00 o'clock; from 220 kmh to 260 kmh on the straight between between Ascari and Parabolica, according to the ingame dashboard, times measured by the ingame Racelogic display. All 10 laps were done in the same session.

Lap 01 - 1:40.0-1:47.0 = 7.0
Lap 02 - 1:27.5-1:34.4 = 6.9
Lap 03 - 1:28.0-1:34.9 = 6.9
Lap 04 - 1:27:6-1:34.5 = 6.9
Lap 05 - 1:27:6-1:34.6 = 7.0
Lap 06 - 1:27.4-1:34.3 = 6.9
Lap 07 - 1:27.1-1:33.9 = 6.8
Lap 08 - 1:38.4-1:45.3 = 6.9
Lap 09 - 1:27.0-1:33.9 = 6.9
Lap 10 - 1:26.1-1:33.0 = 6.9

You can see that with the method outlined above, even on the same hardware there is a discrepancy of 0.2 seconds between fastest and slowest times, although both are outliers. I did not change any hardware between my laps

 

[marcov7625]

I also do 6.9 s and I can understand +/- 0.1 sec between laps. It depends on RPM you change gear. Not half a second or even more

With Lambo and rear wing at minimum I do 6.8-6.9 s. A friend with same setup does 6.2 s... it is 10% difference.

What hardware do you have ? Intel, AMD ...?

 

[marcov7625]

I still see no possibility to change (not only check) the wind speed as I originally wrote. In hotlap mode I have no access to that menu, but if I select sunny condition in hot lap mode and no dynamic weather, wind is not supposed to change for the same track.

 

[Gevatter]

AMD Ryzen 9 3900X & ASUS RTX3080. Overall I do the same laptimes compared to my previous Intel CPU system. Unless your hardware is so bad that it somehow throttles the output to your monitor or cause the engine to lang considerably I still don't see how your PC hardware should influence straight line acceleration that much.

Hotlap mode has static preset conditions to provide an even playing field for the competition. As long as you and your friend both use hotlap mode and clear conditions, the weather conditions will be equal.

I'm still firmly on the side that there is a flaw either in your testing, or that your friend uses different settings from yours. Maybe he miscalculated his times. Maybe have him do the test again in the exact conditions I used above. If there are still discrepancies, maybe you both could provide video of your attempts showing your inputs - if you wanna take it this far

 

[marcov7625]

I think I can do A minus B ...Of course you are free not to believe to my data, but at least I made a comparison and I do not rely only on my data...

BTW this is not a process to ACC. I just want to check if someone got the same experience as I did.

My hw/settings:
i5 9400F + 16 Gb + Nvidia 1660Ti
V sync activated (60 FPS)
1920x1080
No overclock.