Computer is slower after upgrading CPU

[lti]

I have been trying to upgrade a Compaq Presario 2286 to run software that only runs on a DOS-based version of Windows. The original Cyrix MII CPU was replaced with an AMD K6-2/500, which caused performance to decrease. The FSB and multiplier are set to the maximum supported by the motherboard (83MHz, 6x multiplier). I even reinstalled Windows and nothing improved.

Is there a component on the motherboard that could have failed and caused such poor performance? I reinstalled the old CPU and the computer became even slower.

[Topcat]

Re: Computer is slower after upgrading CPU

No, they're both just crap processors. Hunt down an Intel 233MMX, and give that a whirl. If you can find one, you won't have to pay more than a buck or two for it... That was the holy grail of the socket 7 realm. They are default @ 66 FSB, but with some good cooling, a good PSU, and good caps, they do have some decent overclocking potential. I've never seen one that wouldn't run @ 75MHz FSB (which POST's it at 266MHz), and would stomp any K6.

[Wizard]

Re: Computer is slower after upgrading CPU

Yes, I second the Topcat's What I also suggest is if board supports 100MHz with AGP slot at 66MHz, is find a *unlocked* 233mmx CPU and set it to 2.5 for 250MHz. I did that as a trial years ago.

Cheers, Wizard

[lti]

Re: Computer is slower after upgrading CPU

I have a Pentium MMX 200 and its performance is the same as the factory 250MHz Cyrix. After installing the K6-2, every CPU I put into that motherboard gives much lower performance than it does in another board. The Cyrix is even slower now than it was before the attempted CPU upgrade. Before the "upgrade," the performance was similar to other computers with the same CPU.

The motherboard has no AGP slot and only supports an 83MHz FSB. The board has two PCI slots and an empty location for an ISA slot.

[Th3_uN1Qu3]

Re: Computer is slower after upgrading CPU

Maybe the board doesn't have external cache installed. Back then, level 2 cache was on the motherboard not on the CPU. Check for unpopulated sockets. A processor without level 2 cache is very, very slow.

[lti]

Re: Computer is slower after upgrading CPU

Why did it give good performance before upgrading the CPU and now it runs like shit? I can only guess that something has failed on the motherboard.

There is a 256K cache chip on the motherboard.

[mockingbird]

Re: Computer is slower after upgrading CPU

I wouldn't run a K6-2/500 on a motherboard that wasn't designed for it. The VRMs on those motherboards are too weak to handle this chip. That's probably why it's not performing as fast as it should. In Integer applications, K6-2/500 would wipe the floor with anything in its class.

[lti]

Re: Computer is slower after upgrading CPU

It is slow even when underclocked, and all CPUs I have tried in the board since installing the K6-2 are slower than they should be.

When I first installed that CPU, I had it underclocked to 400MHz. Setting the clock speed to 500MHz was only an attempt to make programs run slightly faster after it was discovered that the "faster" CPU was actually slower and the old CPU had lower performance than it did before.

The board was designed to support a K6-2/400, even though the FSB won't go above 83MHz.

[mockingbird]

Re: Computer is slower after upgrading CPU

Which board is it and which chipset does it use?

Did you install the chipset drivers?

[lti]

Re: Computer is slower after upgrading CPU

It is a custom motherboard, part number 387610-001. It has an SiS 5598 chipset. I reinstalled using the Compaq recovery CD, so it should have chipset drivers.

[Uranium-235]

Re: Computer is slower after upgrading CPU

excuse me, is this a serious conversation from 1999? have I walked into a time warp from my freshmen year in high school? hmm, no I don't feel my penis shrinking so I guess not.

dos performance issues and overlocking pentium MMX's? its 2011, and i'll freaking give you a damn pentium 3 slot motherboard with a 667 chip and we can be done with this. i'll even include a whopping 128M PC-133 stick, on the house

[lti]

Re: Computer is slower after upgrading CPU



I don't have the room for more computer junk.

If you think this is useless, you can name a virtual machine or emulator I can use to run all of my old software that will not run under Windows XP, even under compatibility mode. It must be a free program.

The performance issue has nothing to do with DOS. There is a fault with the motherboard.

[Topcat]

Re: Computer is slower after upgrading CPU

excuse me, is this a serious conversation from 1999? have I walked into a time warp from my freshmen year in high school? hmm, no I don't feel my penis shrinking so I guess not.

dos performance issues and overlocking pentium MMX's? its 2011, and i'll freaking give you a damn pentium 3 slot motherboard with a 667 chip and we can be done with this. i'll even include a whopping 128M PC-133 stick, on the house

I was thinking the same thing actually.....but to each his own.... I know a gal still running a celeron 266, she will not upgrade.

[Uranium-235]

Re: Computer is slower after upgrading CPU

I knew a lady who was running a 486 /w windows 95 for years

she bought a compaq with an athlon 64 3500+ and she had it sitting in the corner of her room unopened for 4 years (included monitor) and printer

finally she called us to come install it and transfer her few pictures over

[lti]

Re: Computer is slower after upgrading CPU

I do have a newer computer. I have a lot of old software that won't run on a newer computer. Most of the programs are 3D games. Everything else has a newer version that works properly on a newer version of Windows.

[Uranium-235]

Re: Computer is slower after upgrading CPU

I would imagine you could run Dos without issues on like a pentium 3. this was way before AHCI and advanced hard drive features. that could create an issue

hell run it on a pentium 2. I have one of those too, used to run pfsense in a wireless -> Lan bridge for a friend of mine

[lti]

Re: Computer is slower after upgrading CPU

I could, but I don't want to until I verify that there is no chance of getting this computer running properly.

Also, I'm not using DOS. This computer is running Windows 98, which could run on a newer computer.

[pfrcom]

Re: Computer is slower after upgrading CPU

How much memory do you have in it ?

I think the SiS 5598 chipset caches up to 128mb - anything over that will hit performance

[lti]

Re: Computer is slower after upgrading CPU

Really? This computer has always had at least 160MB of RAM, even before the CPU upgrade. It curently has 256MB. I never noticed a performance hit. I am currently experiencing a CPU/graphics performance issue. It doesn't seem to be related to memory.

[lti]

Re: Computer is slower after upgrading CPU

My reply seems to have disappeared.

I am having an issue with the CPU/graphics performance. The computer always had 160MB of RAM in it until I installed the maximum 256MB of RAM that the motherboard supports. This was a long time before I tried to upgrade the CPU, and it always ran fine.

Another problem is that the computer is slower every time I use it.

Edit: Now my first reply shows up after I post this.