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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Claw22000 on March 17, 2009, 06:12:33 AM
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I currently have a MBX-1200z (http://www.amiga-hardware.com/download_photos/mbx1200z_1_big.jpg) memory expansion card.
I'm pretty sure I'm going to get a Blizzard 1230 IV (http://www.amiga-hardware.com/download_photos/blizz1230mk4_9_big.jpg) Accelerator card.
I have a 68881 FPU on my MBX-1200z is it compatible with the blizzard. (I.E Can I take it off the MBX and put it on the blizzard when I get it? Jacks look the same)
If yes how do I know what way to place the chip?
Thanks
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Hi! there dont waste your time with a 68881 get a 68882 its much quicker and although quite expensive would be imho
the better option. :-D With regards to fitting its quite simple if you look at your 68030 cpu it should have a little arrow type pointer on the top lh side, your maths copro is orientated the same way if I remember correctly.
Hope this helps mate.
cheers
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Can I take it off the MBX and put it on the blizzard when I get it?
No.
It fits physically but the 68881 on the mbx is a 25MHz part and will not work with the Blizzard 1230-IV.
If the 68881 magically would be a 50MHz one, then it would work. Anything lower than that will not work reliably.
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unfortunatly, the short of it is "no".
reason being is that it gets fed the same clock signal as the CPU, and i'm not sure how long an 881 would last at 50Mhz given that its max speed was 25Mhz (or slightly overclocked to sync to the amigas master clock at just over 28Mhz)
the 882 started at 25Mhz versions up to 50Mhz versions.
although i could only get hold of a 40Mhz version of the 882, it seems happy on my blizzard running at 50Mhz.
i belive that they are pin compatable, as for comparitive processing power, i understand that the 882 is about 10% faster at the same clock speed than an 881.
881 = ~240KFLOP/s at 25Mhz
882 = ~264KFLOP/s at 25Mhz
the 882 advantage was being able to be stable at higher clock rates.
for sake of completeness, 040 = ~3500MFLOP/s at 25Mhz
so although they would plug into the same socket, on the blizzard this is not a good idea unless it was running at 25Mhz.
just out of interest, what speed (clock) does it run on your memory card?
--edit--
my bad, 68882's came in at 16 and 20Mhz aswell. how could i forget the early A3000's?
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I once tried 68882@40 running at 50MHz at it would nuke sooner or later. YMMV.
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hmm, maybe i'd better heatsink it and leave the trapdoor cover off. not sure i like the idea of it going pop :-(
but then it gets fired up infrequently. but when it is on, it's usually on for a whole weekend...
and a 25% overclock is pushing it a bit :-D
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Most 1230's on the used market come with a FPU already installed... Least when I was shopping...
I recently bought a 1230 w/ 16MB ram & FPU. I got it pretty cheap on ebay, but it was one of those "I never had a chance to install and test" type sales... Well long story short it had a bad CPU that would crash after 15-20 minutes. Luckily I was able to find a '030 50Mhz on ebay for $30. After swapping out the cpu it's been great. Nothing is easy i guess on 10+ year old hardware... Moral of the story, make sure it has been recently used and tested. If not buyer beware, especially if it's sold as-is.
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@ darksun9210
"just out of interest, what speed (clock) does it run on your memory card?"
No idea how do I tell?