Classicamiga Forum Retro Edition
Thread: FPU - Question - Yes or No?
Tiago 13:28 26th December 2008
Probably you heard this question before:

- Should i get a FPU for a expansion card?

I got the Blizzard 1230 mk-IV @50, i has no FPU should i get one?

I read the "yes" and the "No" before:

- some guys say that FPU is only used in 3D or maths aplications.
- others say that FPU is used in a normal image software
- i even heard that is used for reading mp3...

Being a Floting Point Unit (F.P.U), i can see any other application rather then 3D software or other maths programs, something like Excel, or similars...

If it has a significant advantage, were can i buy one for the blizzard 1230 iV ?
didnt see any in ebay or amikit.

What about speed, my CPU in @50MHz, can i only use FPU of 50MHz?
[Reply]
Fern 15:03 26th December 2008
They aren't expensive. You may as well buy and install one so it's always there if you need it. I would definitely have one, but then I plan on eventually having my 1200 at a "can play Doom nicely" standard so I probably NEED one.

If ever I had money to burn I would get a 1260 card which, being a full 68060 would have built-in FPU and MMU... but they do cost a small fortune!

I have found a few 68882's on eBay but they are the wrong version for your card, which doesn't really help. I can only find the PLCC packaged chips @25MHz, and I believe you would need PGA packaged @ 50MHz. I will keep looking and see what I can find.

EDIT:

http://cgi.ebay.co.uk/MC68882RC25A-M...3286.m63.l1177

This should fit your card. One thing I'm not sure of is what the clock speed is. I'm completely clueless as to whether the chip has a maximum clock speed, but the actual operating speed is decided by jumpers or a crystal on the card, or if they're built at the factory to work at one speed and it can't be changed... This is a question for the experts
[Reply]
Tiago 16:21 26th December 2008
About the Crystal Oscillator,
here is a close up of my CPU and Crystal:
http://www.lobodias.com/commodore_am..._030_mk_iv.htm
witch crystal is it? It says 50.000000M

www.vesalia.de
has a 68882 PGA FPU at 25MHz for 13.90 euros, will it work on my @050 CPU ?
http://www.vesalia.de/e_68882[4803].htm

is there a relation between cpu(MHz) and FPU(MHz) ?
[Reply]
JLPedro 09:29 27th December 2008
The card only as one cristal witch is running at 50Mhz so both CPU and FPU must run at 50MHZ, so a fpu slower than 50MHz will be overclocked.... and no a 25mhz fpu will not make it alive...
[Reply]
Tiago 14:07 27th December 2008
Originally Posted by JLPedro:
The card only as one cristal witch is running at 50Mhz so both CPU and FPU must run at 50MHZ, so a fpu slower than 50MHz will be overclocked.... and no a 25mhz fpu will not make it alive...
Ok, but i don't know if i can get a fpu at 50mhz, didn't find any so far.
[Reply]
Lockon 07:23 28th December 2008
50MHz 68882 is hard to locate and hence high price (above 30 euros).
I recently completed my quest for 40Mhz version (need one for my GVP A530) which is also very pricey (Mr.JJB offers at AmigaCenter France offers it for 50 euros).
[Reply]
Tiago 14:41 28th December 2008
Originally Posted by Lockon:
50MHz 68882 is hard to locate and hence high price (above 30 euros).
I recently completed my quest for 40Mhz version (need one for my GVP A530) which is also very pricey (Mr.JJB offers at AmigaCenter France offers it for 50 euros).

50 euros ?!?!? OMG
[Reply]
Stephen Coates 16:23 28th December 2008
I was told that an FPU is useful as it will help IBrowse display graphics alot quicker.
[Reply]
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