Didn't realise I had been overclocking by 400%

[Mark R]

Yup, that's right. I'd been running several CPUs at 5x their rated speed, and hadn't realised - more specifically, they were running as I had intended, I'd just misunderstood the rated speed!

The CPUs in question are Microchip PICs. I'd bought several, from one supplier - and assumed from the microchip web site that they were 20 MHz CPUs. So, I'd happily paired them up with 20 MHz crystals and everything was fine and happy.

After a few months, I switched supplier, but this one had a bewildering number of variations of the CPUs - and more interestingly for me, some of them were 20 MHz, and some were 4 MHz. So, I pulled out one of my old CPUs, and sure enough it was a 4 MHz one. In retrospect the '04' marking on the original chips should have been quite obvious, but I'd just thought it was a temperature rating or some such irrelevance.

Anyway, here is a picture of one of the CPUs, running at 20 MHz. This one met with an unfortunate accident, and sustained a leg amputation, so it has been used for testing purposes (hence the jungle of wires around it). Note the temporary connection to the crystal, for easy testing.
link

 

[Yeti101]

4Mhz!? The lowest CPU I've ever seen is the P1 133Mhz...... Thats insane! Think of what CPU's have gone through , 2.8 / 4 = 700x the speed in clock rating :Q

 

[CrazySaint]

Originally posted by: Yeti101
4Mhz!? The lowest CPU I've ever seen is the P1 133Mhz...... Thats insane! Think of what CPU's have gone through , 2.8 / 4 = 700x the speed in clock rating :Q

My first computer was an IBM XT Compatible based on the Intel 8088 :Q I then upgraded to a 286-12MHz lol (also went from EGA to VGA in that upgrade - what a difference!)

 

[Jeff7]

Originally posted by: Yeti101
4Mhz!? The lowest CPU I've ever seen is the P1 133Mhz...... Thats insane! Think of what CPU's have gone through , 2.8 / 4 = 700x the speed in clock rating :Q

Yeah, and instead of seconds per operation, it's now operations per second.

 

[OulOat]

Originally posted by: Mark R

This one met with an unfortunate accident, and sustained a leg amputation, so it has been used for testing purposes

You MONSTER!

 

[MustangSVT]

i want to see some 3dmark, ut2003 numbers pls.

 

[Anubis]

Originally posted by: Yeti101
4Mhz!? The lowest CPU I've ever seen is the P1 133Mhz...... Thats insane! Think of what CPU's have gone through , 2.8 / 4 = 700x the speed in clock rating :Q

you never saw a OLD 286 or 386????

thoes ran below P1 133 speeds somethin like 33 and 66 i beleive. o man thoes were the days

 

[CrazySaint]

Originally posted by: TheEvil1

Originally posted by: Yeti101
4Mhz!? The lowest CPU I've ever seen is the P1 133Mhz...... Thats insane! Think of what CPU's have gone through , 2.8 / 4 = 700x the speed in clock rating :Q

you never saw a OLD 286 or 386????

thoes ran below P1 133 speeds somethin like 33 and 66 i beleive. o man thoes were the days

I'm pretty sure the 286 topped out at ~16MHz and the 386 at ~40 (or maybe it was 33)MHz, though its been a long time.

 

[rexfalk]

You kiddies....

My list of processors over the years

Radio Shack Color Computer 2Mhz 68020 (I think, memory is a bit fuzzy)
Intel 286 12 Mhz
AMD 386 40Mhz
AMD 486 100Mhz O/C to 120
Celeron 300Mhz O/C to 450
PIII 500 O/C to 575
PIII 700 O/C to 1000
P-4 1.6 OC to 2.1
The Celeron 300 and up are all still running crunching Seti

 

[randomboy]

Jeez, I'm fresh and green at 20, and I can even remember my first 33mhz computer, DOS menus rule!

I think me and my brother were all jealous when my uncle got his BLAZINGLY FAST 66mhz PC, and we were stuck with our 33

Cant forget the Commodore 64! River raid on that was the bizzzzzzomb

Jeff

 

[skriefal]

I'm pretty sure the 286 topped out at ~16MHz

There were 20MHz (and possibly even 25MHz) 80286 clones available for a while. I believe this was after the introduction of the 80386, however, so they weren't very popular.

And since everyone seems to be reminiscing about their first computer, I'll mention that mine was an Apple II+ running at a blazing 1MHz with 48KB RAM. Later upgraded to an Apple IIe (again at 1MHz) with a "humongous" 1MB RAM and dual 3.5" double density floppy drives . Then to a 386SX-20 PC clone, and then... many more upgrades until now!

 

[Leo V]

I remember my grampa's 1984(?) Spectrum ZX Sinclair -- 3.5MHz Z80 processor, 48kB RAM. pic It connected to the TV and used cassettes for storage, so you had to rewind to start reading from the proper position. It had some fun games and BASIC for it.

PS: He also had a ZX Spectrum+ with similar specs, and a totally awesome Atari 520 ST (1985) with an 8mhz Motorola 68K and 512KB RAM. This one used floppies and had amazing games in color with actual sound/music (not like a PC speaker!)

 

[kingbob]

Hmmmm....Didn't the TRS-80 run at like .75 MHz?

 

[Elminster]

my first computer was a turbo XT, ran at 10 mhz, turned off turbo and it went back to stock 4 mhz or so. was the first home computer bundled with a cdrom

 

[Jeff7]

Originally posted by: Elminster
my first computer was a turbo XT, ran at 10 mhz, turned off turbo and it went back to stock 4 mhz or so. was the first home computer bundled with a cdrom

Wow, a CD drive? Cool. For the first CD-drive I had, we all (my dad and I) splurged a bit here way back when and got a 4x drive instead of just a double.
Don't remember if that was our speedy 486, or the first PC we had, a 386DX 33MHz with 4MB RAM; Win3.1.

 

[ProviaFan]

Woah, that's quite an overclock; I can only dream that my 800MHz duron would do that well.

BTW, my first computer was an IBM PS/1 with a 286 processor that ran at 10MHz, VGA graphics, a color VGA monitor (256 colors, woohoo!), 1MB of RAM, a 1.44MB floppy, and a 30MB hard disk. My dad had an IBM PS/2 model 50 with the 286 processor at 10MHz, VGA graphics, a grayscale monitor, 1.44MB floppy, 1MB of RAM, and a 20MB hard disk. Mine ran DOS 4 originally, while his ran DOS 3.3; I eventually upgraded mine to DOS 6.22 and Windows 3.1.

 

[spanky]

water cool that sucka'!

 

[Occifer]

CrApple II c was the first for me. Seperate color monitor and Cricket sound!!

 

[dmcowen674]

The original TRS-80 Motorola CPU ran at just under 1 MHZ. There was a Hitachi replacement CPU that ran at 2 MHZ with a Crystal change.

 

[Mark R]

Hehe. My original computer was a Commodore Vic20, using a 6502 CPU running at 1 MHz and boasted 3.5 kB of RAM.

As far as I know my Vic 20 still works, although it's been a year or two since I pulled it out of the loft.

My PICs, on the other hand are brand new, only released earlier this year. Like I said earlier, specced for 20 MHz (or 4 MHz if you get the cheap versions), and come with integrated program memory (3.5 k), RAM (224 bytes) and flash (128 bytes). No cache though.

 

[Zap]

I think skriefal is right, in that the 286 processors went to 20+MHz. Intel didn't make it, and I don't think AMD even made those. I think those may have been made by Ti. Basically back in the day other companies were making compatible CPUs (may have been licensed from Intel) after Intel's official end of life for the product. Basically Intel would go on to make the next generation CPUs while other companies made faster previous generation CPUs. The super high-clocked XT machines were like this also. I seem to recall 16MHz XT computers. AMD, Cyrix and Ti made 40MHz 386 chips (well, Cyrix and Ti called theirs a 486 for some weird reason*) after Intel topped out at 33MHz before going on to the 486 platform.

Ahh, those were the days... My 386DX 25 (NOT to be confused with the SX) was overclocked to 27MHz using a crystal. I loved the 486 boards because they used jumpers to switch speeds. Hell, we topped out at 160MHz for the 486 platform using an AMD 5x86 133/33 overbussed to 160/40. I don't think we were ever able to make those things POST at 200/50. Also, 486DX4-100 processors ran great at 120, especially the non-intel versions.

* Those CPUs supposedly had the 486 instruction set and 1k cache (instead of 8k) but ran on cheaper 386 motherboards with an FPU as an option. Real world performance was lower than a "real" 486 at same MHz. Is it or is it not a "real" 486 then? Dunno.