how do i unlock my celeron 300a

[sidelight]

i have a celeron 300a with a mendacino core, i have heard that it uses the same core as a pentium-2 450, my cpu is multiplier locked, therefore proving to be a pain in the ass to get to over 400mhz without using the fsb. It is currently using 66x4.5 to run at 300, whenever i crank it up to 4.5x75, sisoft sandra says it has a pr rating of 401, but it runs slower in "need for speed: porsche unleashed". I have a chaintech 6esa motherboard *cough-hack-cheap-splutter*, but i am only 14 and get jack-all cash. i am running 2x32mb sticks of what i think is 100 mhz ram, might be 66mhz, but sandra doesn't say. i have also heard that if i break of one of the "pins" somewhere that it will unlock the cpu, any help please???

[tainice]

ur chip should come "unlocked" meaning you can freely change your multiplier!!! maybe it is your mobo's fault if you cannot change multiplier at all. Anyway, there is a way to fool your mothterboard to think that your chip is running fsb of 100, even the board itself does not support that high of fsb... do a search here, or ask any loyal intel senior member, such as jay.. i have done that to my 300A, but i forgot how to do it....

[larva]

All celerons, all the way back to the original L2-cacheless C266 are multiplier locked. As far as I know no one has successfully unlocked one.

[Lumberjack]

If you've got good cooling you might want to just make the jump to the 100mhz fsb and see how well it works, as most 300a's were able to do that once upon a time....

[Indyxc1]

The 300A is multipler locked.

It should run at 100 mhz fsb to get you to 450 no problem. I ran my 300A back in the day at 504mhz at something like 2.4 volts for 3 or so years.

Peter

[sidelight]

*bangs head against brick wall*

sorry, notice a couhghed and spluttered about cheap?

my *cheap* "mobo" only supports 66,68,75 and 83 mhz fsb settings, it runs stable, but slow at x75 because of the ram i think, it only supports double-sided, i tried to run the processor at 4.5x83 "373" mhz but i tried to load up windows, got two bsods and my pc reset, i took it back down to 300 and found that overclocking has left a whole load of errors in the system registry which was fine beforehand. after re-installing windows and restoring my registry, everything works fine once more. i tried again, the system just held up at 373 and i barely loaded sandra after about 5 attempts i got in and loaded the cpu module, it said it had a pr rating of 456. i shut down and put the speed back pretty damn quickly after that. thanks for helping:). so it seems the fsb won't hold up so i should try unlocking to get 363 (5.5*66), then i would try (5.5*75) 412, then i won't go any further, i'll be happy,

but i need to unlock, isn't there any physical way to do it, plz help meeeeeeeeeeeeeeeeeee!!!!

[larva]

No, there is not.

[Indyxc1]

Does your motherboard allow you to change core voltage? That should help stabalize it. I do remember there being a way to change the voltage using a hardware trick if you mobo doesn't do it in bios. Maybe not? But if you are interested, search on Tom's hardware should tell you for sure.

Peter

[raven]

upping the voltage should stabalize it a bit better as Indyxc1 stated. whats your voltage at now? ive got a 300a running a 373 thats 4.5*83 and i have it at one above normal voltage. my board supports pc 100 but i cant get it to run stable at 450 anyways =s btw... can anyone help me with that plz?

[myzhi]

300 mhz => 450 mhz is good since FSB (66 = 1/2 and 100 = 1/3 divider) is normal thus your peripherals are running in specs. At other FSB, you peripherals could be the problem. Thanks goodness these days for MBs that lock peripherals bus speed.

[Lumberjack]

Yeah, if your board doesn't do the 100mhz fsb, then at the 83 mhz fsb, your pci bus is running at 41.5 mhz which is WAYYYY out of spec (33mhz is spec), and your pci devices probably simply can't handle that fast of a PCI interface. And no Intel CPU can have its multiplier unlocked or changed unless you have an engineering sample chip....

If you've got 20-30 bucks you probably can get a cheap used bx mobo off of ebay that can run this chip quite a bit better....

Edit: Here's one that is currently at $7 that should do you pretty well:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2062161679

[sidelight]

thanks lumberjack for the info, but i live in australia, sorry about not mentioning it.

my entire system:

2x power supplies
custom case (atx case w/ top half of a 486 case welded on top)
chaintech 6esa slot 1 Motherboard
celeron 300-a
matrox millenium g200 8mb pci gfx card
ess solo-1 16-bit sound card onboard
ne2000 compatible network card 10mbs isa
1x udma pci card
2x32mb ram
1x13gb seagate hard drive
1x2gb maxtor hard drive
1x1.5gb maxtor hard drive
1x 4x8x32 sony burner
1x 40x lite-on cdrom
3x case fans


the welding was messy but the finished job looks good, i will ask mum if i can use the camera to get pics to scan.

one of my mates is going to sell me a bx for $30 aus ($15 us) but i am a bit iffy because it isn't atx, he hasn't got one of them little cards for the other slots either. thanks for all the advice guys. cya

[Kiriakos]

In my secondary system i have the 300A working at 450 with no problems for years ..
ABIT BX6 ..
The point is that not all the 300A it will operate at 450Mhz , i have one of the tested ones , that they do the trick .

[stamasd]

Try to find a used Abit BH6 motherboard, it's the best for your CPU. I've used one with a C300A at 450 from 1998 until recently (now I run a C1.4 at 1.57 in the same motherboard :)). You should be able to find one at roughly $20 (US, don't know the rate to convert to Australian). Try the local computer shops, garage sales, newspaper ads etc.

Again, trust me, this motherboard is the best thing that could happen to your CPU.

[JPSJPS]

Originally posted by stamasd
Try to find a used Abit BH6 motherboard...now I run a C1.4 at 1.57 in the same motherboard
What are the details of your C1.4 In the BH6. Is the C1.4 256K memory? Do you use a "Slocket" then a Socket 370 FC-PGA2 to FC-PGA converter shown here?
Converter (http://www.upgradeware.com/english/product/product.htm)
I am presently using C600 OC to 900 but the 1.4 would be worth doing.
Thanks