It really is ridiculous how many different ways input timing can be affected between the different platforms and versions of SFIV.
Just from Arcade SFIV: AE2012 to Arcade Ultra SFIV, it’s possible timings did not stay exactly the same. But nobody knows, because it hasn’t been (and probably wont ever be) tested. AE2012 runs on Taito Type X2, and USF4 runs on Taito Type X3.
Let’s take a look at the hardware for each, from wikipedia:
Taito Type X²
OS: Microsoft Windows XP Embedded SP2 [3]
CPU: Intel LGA 775 CPU. Supported CPUs include Celeron D 352, Pentium 4 651, Intel Core 2 Duo E6400
Chipset: Intel Q965 + ICH8 (dg31pr +ich7)
Video output: 640×480 (VGA), 1280×720 (HDTV 720p), 1920×1080 (HDTV 1080p)
RAM: 667/800 MHz DDR2 SDRAM. Supported capacities 512MB, 1GB, 4GB.
GPU: PCI Express ×16-based graphics. Supported GPUs include ATI RADEON (x1600Pro, x1300LE) or NVIDIA GeForce (7900GS, 7600GS, 7300GS)
Sound: Onboard Realtek HD 7.1 channel Sound (supports add-in sound cards)
LAN: 1000BASE-T 10/100BASE-TX
I/O ports: 1x JVS, 4× USB 2.0, 1× serial (max 2), 1× parallel port, 2× PS/2, 2× SATA
Audio inputs: AKG C535EB Stage Microphone, line-in (Surround 7.1)
Audio outputs: 7.1, SPDI/FX
Expansion Slots: 1× PCI Express ×16 (used by video card), 1× PCI Express ×4, 2× PCI
Storage: SATA 3Gbit/sec Hard Drives
Taito Type X³
OS: Windows Embedded Standard 7 64bit / Windows XP Embedded SP3 32bit
CPU: Intel Core i5 2400
Chipset: Intel Q67 express
Graphic: AMD RADEON HD 6770
Sound: 7.1ch HD AUDIO
Memory: DDR3 2GB
Storage: HDD 160GB (2.5 inches)
USB: USB3.0 × 2 group + USB2.0 × 2 group
Network: 1Gbit/s × 2 port
Serial: 1 port
Power Supply: 600W
In addition, in Type X³, hardware configuration changes are possible for each game title, following the lineup is as an optional part.
CPU: Intel Core i3/2120, Core i7/2600
Graphic: NVIDIA GeForce GTX560Ti
Memory: Up to 16GB
Storage: Up to 3TB HDD
SSD: 16GB
Let’s check out just a few, of the many, things that could very easily affect input timings from Arcade AE2012 to Arcade USF4:
Game software: From AE2012 to USF4. This should be immediately obvious to anyone. It’s a WHOLE NEW VERSION of the game, and made for different hardware. To just automatically assume, without any testing, that the input timings stayed exactly the same is ludicrous. Almost any of the game’s changes could have unintended consequences.
Operating System: Whether it switched from Embedded XP SP2 to Embedded XP SP3 or Embedded 7 64bit, the change is still a massive one. XP SP3 has 1,174 fixes, and a change to 7 64bit would be drastic.
Chipset: From Intel Q965 to Intel Q67 express. The chipset handles USB ports, which I believe is how the JVS I/O board connects (If I’m wrong, you can ignore this). Anyone who’s a hardcore PC gamer should know first hand how your chipset can affect your USB’s performance. Worse yet, if they’re using a USB 3.0 port to plug the JVS I/O into for the Type X3, it’s even more of a possibility for input timings to have changed, due to backwards compatibility with USB 2.0 being buggy as fuck with a lot of drivers.
GPU: I haven’t been able to find exactly what graphics cards AE2012 and USF4 use on their respective arcade machines, but it doesn’t matter, as they are certainly not the same. Let’s assume AE2012 uses the nVidia 7900GS and USF4 uses the nVidia GTX 560 Ti. This is a major area where input timings can be altered. They both use different driver versions, each with it’s own set of bugs, fixes, and features that are not shared with the other version. Take a look at the changelogs of the drivers from when the 7900GS came out all the way up to when the 560Ti came out and you will most likely be amazed at the kind of shit goes on with graphical drivers. Major features such as the way anti-aliasing and vertical sync (to name a couple) are implemented get broken/fixed/changed, sometimes on a game by game basis and sometimes overall.
Just between arcade versions, the possibility for different input timings exists. Yet here we have seph13, who hasn’t tested either arcade version, and is running an AE2012 rip with emulated JVS I/O on his PC.
Let’s look at a few of the ways his PC setup may differ from the arcade:
Game software: He’s comparing an Arcade rip of AE2012 with console USF4. Read above.
He says he has a more powerful graphics card. Refer to the GPU section above to see why this may cause discrepancies. He also almost certainly is not using the same GeForce driver version that is on the Type X3.
Emulated JVS I/O: As said above, the JVS I/O connects via USB (I believe) to the system. He doesn’t have an actual JVS I/O, and is emulating it. He most likely has a different chipset, with different drivers, and who knows what method of input he’s even using. Is he using a USB game pad, stick, or keyboard? Maybe he’s using a PS/2 keyboard? All of these devices could have very different input timings (even within each category: many sticks have different input timings), and who knows what kind of fuckery could happen with emulated JVS I/O.
Monitor: I don’t know what monitor they use in the arcade setups, and I believe seph13 said he is using the evo monitor, which if it’s still the same, would be the ASUS VH236H. The VH236H has 10ms of lag according to http://displaylag.com/, and who knows how much delay the arcade monitors have.
Other software: Any software which interacts with operating system at a low level (such as drivers) can mess with input timings. It’s even been speculated (but completely unproven as far as I can tell) that things such as Sun’s Java and Adobe’s Flash can increase input delay: http://www.overclock.net/t/1433882/gaming-and-mouse-response-bios-optimization-guide-for-modern-pc-hardware-2013-r0ach-edition Again, practically nothing in this overclock.net thread has been scientifically proven, but it’s something to think about as a possibility for discrepancies between an actual Arcade machine, which would not have such extraneous software, and a regular PC, which typically does. But even if you were to format and run a clean install of whichever embedded OS either arcade system uses, you would still have a litany of other differences, some of which are listed above.
So in the end, whether seph13 is right or wrong, nobody knows, and his testing is 100% flawed and should be completely disregarded. The only conclusion you can draw from seph13’s testing, is that he has no understanding of what the fuck he is doing.