Do 386 PCs have trouble with newer ISA video cards as a few of my newer cards have visible lines up and down like my 16 bit Trident TVGA8900D but my older 16 bit western digital WD90C00-JK works fine

These symptoms make me think the PSU is going out of spec once in heats up enough. I'm not sure what exactly are those lines like though, if you can take a photo. If you have a multimeter check the voltages of the PSU output when the problems appear.

Heatsinking the CPU will be beneficial to it.

I haven't had any problems with various ISA video cards on my 386 boards, I was using a TVGA8900D in my 386 until I replaced it with WD90C30 due to its faster performance.

from what I understand it only happens with 1 video card and not others? it would be the card most likely then, but heatsink on cpu never hurts anybody

GabrielKnight123 wrote:

Hi all, I have a 386 system running well but [..] the CPU gets hot up to a point that it might be
why I see lines going up and down the screen [..] im guessing its the CPU getting to hot, If I put some double sided tape
I got with my Raspberry Pie and put a heat sink from a socket 5 or 7 on the 386 should this be ok ?

treeman wrote:

from what I understand it only happens with 1 video card and not others?
it would be the card most likely then, but heatsink on cpu never hurts anybody

No, a heatsink wouldn't hurt. If it makes you feel better - I installed heatsinks on my Pis, too. 😉
If you still have concerns and want to be on the safe side, get a cheap PSU tester.
They do check ATX PSUs mainly, but some also have adapters included for AT PSUs.

Also note that intel chips from that era may usually get a bit hotter than AMD chips.
If memory serves, AMD used the same intel core logic and microcode, but used a so called "static design".
Which means, an am386 requires less power and has no minimum-frequency.
It can also halt the CPU core any time if required (idle loops).
For DOS, there's power.exe and DOSIdle (freeware) which can put the CPU to sleep.
(For Win3.1, there's WQGHLT which works in 386 enchanted mode)

Edit: Quotes fixed.