Warning: Incumbent rambling before getting to the point...
It's been a while since I posted. Last I posted, I just couldn't figure _why_ the following regarding Tekken 4 & 5:
1) Getting poor performance (Pentium DC 5400 (2195 STR) + 2GB RX460 -- at the time of writing this) when people with lower STRs were playing okay.
2) Why _software_ rendering was anihilitaing (by 2x-3x speed) hardware rendering. Not that software drawing gave me full performance.
Neither could anypony else. Everyone said basically "Tekken is just one of those games that's buggy."
Well, I'm happy to report: I figured it all out.
PLEASE CAN AN ADMIN ADD THE SUMMARISED VERSION (za TL;DR bit) OF THIS INFO TO THE OP AS WELL AS TEKKEN 4/5 FIXES, IT IS VITAL, at least on OpenGL & Linux:
*. I tried updating to latest stable drivers for 460...no.
*. I tried a few speed hacks...no.
*. Then I tried disabling "Full Depth Emulation"....yes!
So why is this? Well, basically because your GPU _does_ matter! Mine at the time is an RX460 (not a bad entry-level and I got a ~132USD card for ~86USD (converted from ZAR at 16:1) ). Okay, so why was it choking? Well, I don't know if it's the graphic libs PCSX2 uses (I assume you're not writing in straight OpenGL since you're supporting DX too) _or_ AMD's driver stuff up. Last AMD update _did_ improve my FPS in hardware mode, but not enough. Tekken should be less taxing than RE4. Buuuut, I forgot that although the map size and number of objects is less, there's more detail (such as dresses, unique objects (unlike RE4 where the badguys are mostly the same object) ). There are plenty effects, too.
Soooo... I seem to be stating the obvious. But, like in all good detective novels/plays, I've gathered you all in one room for a big reveal that's preceded by a lengthy monologue.
According to the plugin, enable Full Depth Emulation helps with blurring and depth-related effects (would've never guessed the latter). So when I disabled it, I expected a shtty experience, especially on Tekken 4 on the freezer stage. But I gave it a shot an boom, looked fine. Not quite as I recall, but good enough.
So why? What gives? My CPU use was at minimal on all 4 threads (and my temperature was low).
You'll find the answer in _somebody's_ code: the plugin writer, the author of the library used by the plugin writer (assuming it's not straight OpenGL calls), or AMD as suggested before.
Anyhow, regardless, there's an unavoidable problem, it probably cannot be fixed through optimization. so you need more horsepower to overcome it.
Unlike focussing on high-end CPUs, I'd say a _decent_ single-thread performance CPU (>=2000) coupled with a better video card is best. I think that a Pentium 5600 would definitely do, but an i3-8350K should be 100% smooth. An aside: if you have a little extra to spare then i5-9600K wins hands-down as the most cost-effective chip because it's 25% more expensive but gives you 50% more cores/threads (6/6) along with an insanely-high STR to make it a great general gaming or workhorse CPU. That said, I use a Pentium 5400 and my CPU use on all four threads has yet to hit even close to 40% with PCSX2 running.
My video card = "Powercolor Red-Dragon: AMD RX460 chipset, 2GB DDR5 memory, very quiet and _no_ extra power needed (as in purely PCIE powered - ironic on a 550watt PSU)". I believe the last part is actually a problem: PCIE powered (and maybe having pretty cheap-looking cooling). Rethinking it, I'd recommend a newer card, say RX580, and one that's PSU-powered. At build time, my budget was limited and I was lucky to get what I did. I'd be stuck with an AMD Ryzen and iGPU otherwise (and no, AMD Ryzen is not great unless all you want is a budget gaming/media). Ryzens have a great upgrade path to mid-range, but you'll hit a plateau better spent on a cheap intel CPU and entry-level video card which you can gradually upgrade (my next focus is now an i5-9600K because it's worth so much more than the i3-8350 now that the 8350 is no longer on special at my supplier). Ryzen solutions are more cores at cheaper cost than Team Blue, but for PCSX2, we know that's no good. I have seen RE4 played on a Ryzen, but not Tekken 4/5/TT. I'm much happier with what the end result of my chosen path will be.
[ TL;DR ]
PCSX2 will run great on just about any Coffee Lake chip with a decent STR, even a Pentium. On the other hand, you need a better graphics card than an old RX460. I'd say RX580 or more to satisfy hardware rendering. This is contrary to the advice in the OP, but heed it if you use Linux & OpenGL.
You can __forget the graphics card altogether__ if you grab an i9-9600k and rely on software mode. You may even get away with this using the aforementioned i5-9600K (nearly half the price).
One last note: putting your ISO rips on an SSD probably will _not_ help (I haven't don't enough benching but so far tests support my next statement) because the PS2's read speed is nowhere near the speed of an old 5400RPM HDD.
Hope this helps clarify. I spent a lot of time on this research and benching.
PS: The snow effect is cute, but for a moment I thought it was something on my monitor, lol.
Ryzen 3600X || 8GB DDR4-2666 || GTX 1650 4GB || Debian 10 || PCSX 1.7 (App Image), 1.5 (Stable), 1.4 (EOL)