Hi there,
A lot of things have kinda come together on my quest for A4000 res-erection, and it's little adventure, so this is going to probably be a bit of a story!
stream of consciousness ramble coming up...
i have the 5volt version of the mediator A4000Di Mk-II, and it's all in the original A4k Desktop case. the reason i've pretty much only relatively recently got round to playing with it (enough time for Elbox to release a new version of the mediator since i bought my meditator way back when), was i thought my actual machine was toast. it had a relatively recent - in it's life at least - flexATX psu installed pre-me getting hold of the machine. only a couple of months later in my hands it died. Of course i didn't suspect the brand new PSU, so i was buzzing traces/sockets, cleaning any non-existent Battery corrosion. trying anything to get life. but nothing.
cue house move, cue kids, time (years) pass.
then for some reason i test the PSU. and wouldn't you know it, it's dead as a door nail. Turns out the original A4k PSU is able to push 180Watts on the 5Volt Rail. PC PSU's usually drive most of their juice on the 12Volt lines. so the FlexATX PSU i *was* using could only drive 40-50Watts on the 5Volt rail. Amiga's are all about the 5Volts. 12Volts is just really for audio op-amps, and drives. So the flexATX psu had thrown in the towel.
so i bit the bullet and picked up a SFX PSU that could run at least 200Watts on 5 volts - turns out you have to go to around 500W-600W range to get that. and boom, we have life. amigakit pretty much next-day'd me an ATX to A4k PSU adapter and we're back in business - and i was pretty ecstatic about it all too!
so. if you are going for a modern PSU swap, check the 5Volt rail output.
now, i was doing some benchmarking for another forum. Everything i've got with an FPU got ran, and results dumped into Excel. The only thing that threw a major question mark was the A3640 - it... was.. so... SLOW... tested in both my a3k and a4k. same numbers. same results.
the only thing i could put it down to was the ram performance of the A3640, which... quickly turned out to be pretty disappointing. it didn't take too much digging to find that this little dog and pony show of access and transfer speed was repeated on the Z3 bus as well.
Now, i just want to stress this, but. PERSONALLY, and this is PURELY MY OWN OPINION, on what i've figured out during my time with the kit i've had access to, that i think the 060 conversion of the A3640 card is a waste of an 060 CPU. I really don't mean to pee on anyone's parade, and i bow down and grovel to the guys with the skills to create the A3660 cards. but think see the A3660's as a stepping stone to creating a new better card. like how the TerribleFire cards were created. first there was a TF020 card with no ram, no IDE or FPU and performance sucked. but it was a learning experience. then there was an 030 card with 2 meg ram and IDE, then step by step. up to to where they are today, and where they are going.
Do i think the A3660's cards are worth the money i'm seeing them go for? yeah maybe. in regard to someones time, awesome skill, effort and just all round dedication to bring one to life. Do i think they are worth it in regard to actual performance? no. Should they be regarded as a worthwhile performance upgrade? sure, if all you've got is an 030. otherwise....
I mean, yeah an A3660 can put up some pretty numbers in sysinfo or whatever you run, and also of course, an the A3640 show a clean batting average as to where you'd expect a 25Mhz 040 to be. but then if the cpu test loop fits in the cpu cache, it's going to show the CPU performing absolutely spot on to where it should be. however, the fact an A3640 can be troubled by a Blizzard 50Mhz 030 running something that needs the cpu code to rely on external ram. this should not be a thing.
10mips 030 verses 20mips 040, i should see twice the performance. not around 10%.
i am willing to bet anyone with the ability to test it, and i will happily revise my above ideas if proven otherwise, ten post-brexit Great British pounds stirling, that an A3660 or 060 converted A3640 will get worse FPS in quake, a worse povray render benchmark test, or anything else you care to throw at it, than an 040 card backed with it's own local ram. be it a warp engine, or cyberstorm, at 25Mhz clocks whatever. first one to prove it's better numbers wise gets the cash.
so, moving on. the A3640.
bustest Mediator Zorro3 performance to radeon9250. lets pick the best number. 6meg a second.
bustest cybervision64/3D Zorro3 performance. again, best numbers. 6 megs a second.
bustest bigram256 Zorro3 performance. 6megs a second.
drive speed test of a USB thumb drive on a rapidroadUSB card on an XSurf100 in Zorro3 mode (yes i did finally sort it out, and yes it was my fault for not reading the advice on the website). But anyway, co-incidentally, would you believe it, 6meg a second.
hmmmm.
P96 speed on Radeon vs CV64/3D. the numbers were not the same, but pretty darn close. same for the graphics bench in SysSpeed. so i'm feeling a bottle neck somewhere. how on earth can a Radeon chip from this century be honestly going toe-to-toe with a chip from the last century? reading up on the Radeon Driver. i'm willing to put a good amount down to driver maturity - its no small blessing that this driver even exists at all. I suspect then it's a case of; if you can, get the Voodoo3 card. voodoo3 driver and support has been around a lot longer - and hey, Warp3D support too. My understanding is that Warp3D is pretty much NEVER going to be a thing on the Radeon under OS3.x . EVER. which is a shame - and that's something i 'm pretty gutted about... we have the hardware. just not the software to open that floodgates.
anyway. bottle neck. Radeon roughly equals CV64/3D in performance... so why have i pulled my Mediator card...
the mediator does nothing that i now don't already have a decent zorro solution for. originally when i first got my A4k, i had nothing, so i bought the Mediator to fill that RTG graphics card feature that my loaded A3k has spoiled me with - as the mediator was pretty much the only game in town. Plus a Lan card, and sound card (which i've lost somewhere). Anyway. before my Mediator arrived, my A4k "died" so i thought, and i ploughed on with my A3k. in that time the xsurf-100 and rapid road were released. big Zorro Ram cards became available, and pretty much because my mediator experience was overall so .... frigging fraught with little gotcha's and the like. and the boot time! good grief! setpatch! the floppy stopped clicking for so long and no video output i thought the machine was dead! only when i accidentally left the machine for long enough i realised it was just the "normal" boot process.
so i got hold of another CV64/3D last week "just to see" if running a 4meg virge chip was any better than the pain of the mediator and radeon combo. no boot time hold ups, no weird crashing. machine is solid as a rock seemingly so far, and usability is back to par.
also tested the lan card performance. the 100meg card on the mediator's PCI is, just like the graphics cards, like-for-like speed wise with the xsurf-100 i've got in there. so yeah. again, suspect bottleneck.
don't get me wrong, i LOVED having a massive amount of graphics ram, and not having to care about display resolution, refresh or depth. but an amiga's workbench and display environment just starts to get a bit silly at anything over 800x600 or 1280x1024. icons, and window elements too small etc. and stuffing a 24bit display with 8 bit alpha channel over a 6meg/s link? no. just fuggedaboudit... 8bit depth to be useable. on the radeon, even then icon redraw sucked. and i'm talking countable seconds to refresh a window after moving another window out of the way so it was visable.
The Lan card "just worked" which was great.
i never got a USB card. that whole thing about the "wipe the disks RDB" in the Elbox drivers if a non-legit USB card was plugged in or something; left me with a sour taste in my mind - so i'd never get a PCI USB card for that risk/reason.
The sound card would have been the only redeeming feature of having a PCI bus available, and i lost that card. i even bought a terratec something off ebay, that was dead on arrival. so blah. whatevs.
How to fix the bottleneck.
I distinctly remember getting 14+meg a second on bustest from a cybervision64/3D card, back when i was running a cyberstorm2/040 card. So i recon, any card backed by some of it's own ram is going to crank up the Z3 performance, and therefore your mediator experience should also pretty dramatically get better. I did consider the revised set of PAL's or GAL's you can get for the A3640 which take a couple of clock cycles out of a ram/bus wait delay or something. but again, effort outlay for return. further discussion on the subject convinced me not to get to involved or hang too much hope on this avenue of inquiry. Seems to just make the A3640 a "little less crap" than a "make it what it should have been" sort of thing.
So i won't sell my mediator. But it's put away for now, and i'll MAYBE re-visit it once i have something of worth in the CPU slot. i just cannot be arsed to strip down my A3k for the Mk3 that's tucked under the drive tray for another round of testing...
i hope you have a more pleasant experience than i did, and i wish you luck in your endeavours going forwards