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and bonus question, would it be possible to replace the cpu and cpu crystal with 50mhz to allow the A2630 to run at 50mhz? i imagine other parts of the card might have issues with it.. seems to simple.. like everyone would be doing this if this were easy.. but still i have to ask! 
The FPU will put additional load on the data bus. My general recommendation is to completely remove it, and also reduce to on-board 2MByte instead of 4MByte to further lower the load on the data bus.
BigRam2630 will ONLY work with the 2630 at exactly 25MHz. It does not work at any different speed - only the stock speed that Commodore has provided.
Back in the day, I remember GVP sold plenty of 33/40/50MHz 68030/68882 accelerator cards for those looking to 3D render w/the fastest FPU options. Later, 68040 cards came on the market (~1991-2 or so), and the rendering software houses recompiled their code - further optimized for it's reduced inline superset FPU instructions. After C='s demise, the 68060's eventually showed up, and rendering performance went even higher.
It's my opinion that the presence of the FPU on the C= board will either be fine, or it won't, with the BigRAM on it at any clocking. The FPU's clock rate is asynchronous to the CPU/bus clock. It's the mere load of the additional circuitry that is the greatest factor.
Good to know about the clock speed of the 030.. i figured 25mhz would be fixed. the A2630 says it will work with 33mhz 68882 so if the 50mhz doesn't work out.. 33mhz could be an option I would imagine?
The clock speed of the 68882 will most likely make no difference - if you have one that is rated for 50MHz, it'll work at 50MHz in the 2630 as well. However, the bus load still stays the same, and it will influence reliability of the BigRam2630 card. You may need to exchange the CPU for one with mask F91C, as that has a considerably lower pin capacitance and will therefore work much more reliably with the BigRam2630
That said, if you can get a genuine 50MHz FPU (which is kinda hard these days, as most of the FPUs on the market are fake), it will also have a lower pin capacitance.
thanks Jens for the insight! OK I found a F91C 68030 for a fair price so I'll give that a go. Hopefully not fake.
Here are the chips I have in the two vintage cards.. the others I have are newer.. a TF536 and an ACA1232 cards I have..
2030 Turbo
CPU
XC68030RC20B (20mhz?)
07B67R8840
FPU
the FPU on this card is one of those chip socket types, not pins so it's not usable for my A2630
A2630
CPU
MC68030RC25B (25mhz?) from my A2630
03C43C43C
QEHE8949
FPU
MC68882RC25A
4B96M
QEBF8945
If I got a 50mhz 68882 FPU.. will sysinfo be able to detect it's intendent speed from the CPU?
No. The mask can't be detected with simple software means. I can detect the CPU shrink level by measuring certain sub-cycle timings, but I haven't done these investigations on FPUs yet. All my attempts of getting non-fake FPUs were totally unsuccessful - they were all obvious fakes and I've sent them back (lost the escrow money, though... multiple times).
I found a 25mhz 030 with the proper F91C. this thing looks like it's definitely used.. could still be a fake but i'm guessing a not top of the line 030 is less likely to be faked?
also i found an FPU seller is in the same state as me (Massachusetts) so i'm not saying anything is certain in life but i'm going to message him to confirm how they know it's a real 50mhz fpu..
It may be a fools errand but I have to at least make one attempt at this before i reside myself to using a vanilla A2630.. I want to take this chance to do some A/B/C comparisons of TF536 / A2630 / Apollo 2030 and see how they hold up with / without various FPU configurations. if it all fails spectacularly.. i'll know I tried..
1. how do i reduce 4mb to 2mb? i don't see any jumpers.
You need to remove the memory chips. They need to be physically gone, as not the RAM capacity is the problem, but the pin capacitance (an electrical property) is the problem.
2. is there anything i need to do to my GVP hc+8 to speak optimally with the A2630 / big ram? It has no on-board ram.
If it does not have any local RAM, it's already perfectly set up.
You need to remove the memory chips.
these all need to be removed? i recall you saying go from 4mb to 2mb so that means leave some of them? which ones? or do you mean i should actually go from 4mb to 0mb? my card has the full 4mb set of chips on it.
Not all of them - only the 2MB that make up the "2 to 4MB expansion", then set the jumpers accordingly.
If it does not have any local RAM, it's already perfectly set up.
oh, yea i think this was mostly in regards to comments I recall someone saying about 7mhz and 14mhz or needing to clip some resistors or something? Maybe unrelated..
Which chips need to be removed exactly? there are no jumpers on this accelerator that i can see.
We're here to support, but mainly our own products. We can't provide comprehensive support for the overall system, as we didn't make the majority of it.
Here's a description of jumpers, found using a popular search engine:
understood, could you at least confirm which chips go away for 2mb? i follow the rest of it overall. this is the only outstanding question and one that has serious consequences if done incorrectly. thank you so much for your support! You're one of a handful of folks who can speak with any authority on this kind of hardware.. the big ram card is great.. i've also bought the aga mk2 and 2mb chip ram A2000 mod from you all. I just don't want to botch this with something as irreplaceable as the A2630 or at least incredibly expensive to replace!
Here's a closeup of my 2630, which has the expansion chips in sockets (well, sort of). These are the ones that need to go if the F91C CPU and removal of the FPU don't solve the problem.
The last reply was more than 365 days ago, this thread is most likely obsolete. It is recommended to create a new thread instead.
