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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Abou27 on January 08, 2004, 08:24:13 PM

Title: FPU Mhz < CPU Mhz
Post by: Abou27 on January 08, 2004, 08:24:13 PM

Hi there,

  My Blizzard 1230IV 50 Mhz has no FPU :-(   I have been waiting for a month and a half for a 50Mhz FPU to arrive from AmigaSuperBit but no luck.  Can't seem to find anywhere else that offers them.  However, I see plenty of places that do 40Mhz ones and was considering ordering one.  This made a little bell buried deeply in my head start to tingle a little.  I seem to remember hearing that one shouldn't pair a CPU with a lesser FPU.  Is this true and, if so, why?  Would it damage my accelerator if I tried?

Title: Re: FPU Mhz < CPU Mhz
Post by: x56h34 on January 08, 2004, 08:33:49 PM

Get it from Vesalia.

They have a 40Mhz 68882 PGA FPU which has passed testing at 50Mhz. I've been using one of those in my B1230-IV for months and then I sold that whole card on eBay, but for that time period I haven't experienced any problems with the 40Mhz FPU running at 50Mhz.

Title: Re: FPU Mhz < CPU Mhz
Post by: Lemonty on January 08, 2004, 08:34:20 PM

I bought a 40mHz FPU for my BlizzardIV030 (50mHz) a few years back. At the store they told me there would not be a problem. True, the FPU works ok for about half an hour after which FPU related apps start failing. I guess heat is the main problem. My A1200 is a standard desktop one and has very limited ventilation (particularly in the trapdoor area even with the lid off).
I guess you are ok with a 40mHz FPU provided you have cooling sorted or your 1200 is towered.

Title: Re: FPU Mhz < CPU Mhz
Post by: Abou27 on January 08, 2004, 08:54:42 PM

Cheers guys - good to see both sides!  I'm in a desktop and want the FPU to speed up Real3D mostly so will have to give this some thought.  I suppose they are not that expensive to try one out as long as they don't damage board!  Anyone else have experience of this?  See if the 50:50 split continues!

Title: Re: FPU Mhz < CPU Mhz
Post by: Brian on January 08, 2004, 09:43:15 PM

25% overclocking is quite abit so you do need some kind of cooling on it, especialy as you're saying you're going to put heavy useage on it. I belive a coolingplate should be enough but if you experience crashing FPU apps then add a fan. I doubt that the FPU will damage the rest of the turboboard even if it was to break down.

Title: Re: FPU Mhz < CPU Mhz
Post by: x56h34 on January 08, 2004, 09:49:43 PM

@Brian:

I agree in general, however the ones sold at Vesalia have been tested to run OK @ 50Mhz (it says so in description). I guess the best thing is to try and see, as you've suggested.

Title: Re: FPU Mhz < CPU Mhz
Post by: Brian on January 09, 2004, 10:08:10 AM

That it's been tested and working at 50Mhz doesn't say it doesn't use any cooling to do so... much like 060 going at 66Mhz.