After some time away from rF2 the new online experience got me going again , for a while, until I noticed some performance problems. On the Portland and Radical combo, I was getting 39 FPS on the start line. Granted that was with 20 opponent cars visible and fairly high settings, but felt like it should have run better on my single screen setup. rF2 has had issues with high PCIe bus usage in previous builds and I reckon complaining about it here. At some point it was solved (at least for Nvidia) but now it's back again it turns out. When I tested the same replay again using PCIe 2.0 set in BIOS, FPS dropped from 39 to 24. Interesting... Now it turns out there's a new feature since a few years ago called Resizable BAR for Nvidia or SAM for AMD. What it basically does is to allow the CPU access to your GPU's entire VRAM at once instead of being limited to a maximum block of 256 MB. If you have a motherboard that is not from the recent two years or so, this feature is most likely disabled, but you may still have it available or get it via a BIOS update. With the full frame buffer available, voila! I am now getting 62 FPS when testing the same replay, which makes the difference between playable and unplayable in my books, so a roughly 60% improvement from changing a setting that most people are probably not aware of. @Kelju_K had observed this on Discord as well, but I couldn't find much discussion on this here. In below screenshot you can see the performance improvement and MSI Afterburner graphs. P.S. If you have a PCIe 8x card like I do (AMD RX 6600/7600 series or Nvidia RTX 4060/Ti) combined with a motherboard that doesn't support PCIe 4.0, you are likely to see the most performance improvement from changing this setting. If you have PCIe 4.0 but limited to an 8x card or PCIe 3.0 with a 16x card, you may still see improvements, but a bit smaller probably. If you have PCIe 4.0 and a 16x card, improvements will probably be the smallest.
hello nice post. I recently moved from AMD GPU (6950XT) to a NVIDIA crad (3080 12gb) to get better VR performance its true that SAM was boosting fps on my machine, but I still haven't set up ReBAR with the RTX3080 because of some MB Bios issue. the 2 graphs you are showing are with AMD card or Nvidia?
Have in mind that REBAR will cause fps drop or problems for games that doesnt support it and you might have to turn it off again for games like Alan wake 2 for example that doesnt works good with it. Starfield on the other hand likes it and it is optimized for REbar.
Yes they are with AMD RX 6600 XT on a PCIe 3.0 motherboard. After reading some further on this it turns out the Nvidia feature works a bit differently. For AMD GPU's it's enough to just enable it in a supported motherboard, but Nvidia REBAR also requires their driver to have it enabled on a per game basis. So unfortunately I can't confirm if this works at all for Nvidia cards in rF2 and generally it seems this feature helps AMD cards more than Nvidia.
Yes. Also requires a motherboard that supports it and for it to be turned on in the motherboard BIOS. 3070 is a PCIe 16x card, so your gains will probably be small if you already have a PCIe gen 4 motherboard.
But if you run your harddrives in legacy (and not uefi) you cant activate BAR/SAM. Just tried and it deactivated my legacy mode.
Checked this. Pretty interesting information and I updated my motherboard (MSI Z790) as my MSI 3080 Gaming Z Trio was already up to date. Option was activated by default (mobo) and also in NVidia Studio driver. From what I remember in order to compare with VR the gain of FPS is about 2 or 3. If we stick to some articles around the performance should increase from 2% to 10% (with 10% I would have been the lucky one). As my GPU is a PCI4.0e capable one it is ok - running triple screens with 7680x1440 at 144 Hz is more impressive (for what reason ever) as I do not notice any FPS drop which I noticed from time to time without the option. I did not read that much about it yesterday, but I would say it helps in some aspects. And as with Nvidia driver being able to enable or disable the option on a per application base I would say it is worth to check out which application participates from it and which one not.
Oh I am just noticing that one I still haven’t gone back to gigabyte if I can safely downgrade my MB BIOS to recall the use of rebar on my rtx3080 hopefully yes cause any fps in VR counts as you k no w well
That's what I think, too. On a screen setup it does not matter that much if we get 144 or 121 or 93 FPS - IMHO - but with VR every single frame counts ... to me there is a noticeable (optical) difference between using 90 Hz and 75 Hz refresh rate on a HMD, but if I can get stable FPS rate at 75 Hz I am using it instead of accepting / living with FPS drops while refreshing at 90 Hz. IMHO FPS drops - let's say from 90 to 85 when you are on 90 Hz refresh rate - are much more noticeable and disturbing than the impact on immersion running at 75 Hz refresh rate without any drops. The discussed option (resizeable bar) needs benchmarking on a per app base - IMHO - but I think it is worth doing it ... and as I noticed yesterday, I was using PimaxXR as "VR engine" while running the Pico instead of SteamVR or openXR :-( So I need to do some benchmarks again ... (I am not expecting worse results)
Totally understandable I am very sensitive to screen tearing and frames stutter so I will prioritize a smooth experience But if I can have better visuals than with my Q2 then I will become an happy Pico camper being with the P4 or the Neo3 I have not written off totally yet If only I could set an halo strap on this thing taliking frames with the recent meta v59 update that broke opencomposite and the developer not supporting a fix I had decided to reset my RF2 and other Sims to vanilla steam files then use the opencomposite per Game openxr DLL that people made available on discord RF2 runs fine on my Q2 like that with locked 90fps in most situations including night and rain with some minor graphics tweaking with the Pico headsets what is the right approach step by step is where I am struggling with first topic is the streaming assistant For now I use the pico one with frequency at 90hz and max resolution all that through DP cable of the Neo3 then via USB for the Pico4 i read people praising VD instead ok I can invest in that but I also see some YT videos talking about plugging Ethernet directly to the headset What’s the merit of such solution? Is that for people willing to use VD but have poor wifi? Then resolution and SS With my Q2 resolution in the meta app is all cranked up to max And I don’t touch steamvr because I bypass it with opencomposite with some sims like RRE I add SS but in case of RF2 I leave it as it is with the Pico how to set resolution and SS IN PICO software in steamvr. and even like I start to read it in the pico windows drivers? finally to gain fps how about the openxr tools? I am using openxr toolkit for example with my Q2 to manage various parameters including FIV rendering how about with the PICO? sorry many questions and this thread is not evenVR or PICO related so I might ask in the other threads not to bother the OP here
I did this, but it didn't improve my fps. I upgraded the BIOS, turn it on, checked in the nVidia control panel to confim that it is turned on, and tested in the game. I didn't notice any improvement. The fps at race start is still between 60-70 depending on the track and time of day. Only during the race it increases to 70-100 depending on the sector of the track. I have Ryzen 3700x with B450 motherboard and RTX 3080.
Good information. You have PCIe 3.0 as well, but RTX 3080 is a PCIe 16x card unlike my 8x GPU. Might be that mainly AMD cards get a performance boost from this feature.
