Ketchup 😁 Ever put tomatoes in an oven? Those things transfer heat so good it accumulates heat pretty much.

Since as u said it doesn't matter that much, I don't use something expensive, in my case a cheap compound from Titan.

I have a big tube of Arctic MX-2 I use for everything.

where is that guy who used toothpaste... 🤣

I use Arctic MX-4. I bought a tube once for my SB i7 (MoBo change, so the pre-applied compound had to be replaced), and so far I don't think I used half of it... so I keep using it for retro-systems or whatever. But if I didn't have that tube I'd probably just use some random cheap compound.

I've used AS5 for years - in some cases on hardware that today we call "retro" back when it was brand new. 🤣 Never had a problem with it either. On the cheaper side, ASC isn't bad, but it can get kind of tacky/grippy which may be a problem in some applications (OTOH, its GREAT for sticking ramsinks on, and being able to remove them again later 🤣 ).

I really don't use thermal compound at all, unless i'm working with old CPU's that run very hot. Texas Instruments and Cyrix 486 DLC's for instance, and Cyrix 6x86 and AMD K5 CPU's.

i always use cheap ones, even on modern computers. while they are cheap, they are light and i can paint them very thin.

For 386, 486 and low clocked P1s, I don't even worry about thermal paste. They don't get hot enough for it.
Otherwise I use the same stuff as on the main machine: Masscool Fanner-420. $3 does a whole bunch of CPUs.
Keeps my C2Q under 55c under 100% load with a so-so HSF

I have the 25g AS Ceramique syringe that costs about $8. Lasts me years.

I've been using this for so long I don't even remember when I got it ^^:

I use it on every CPU I have, and works just fine for me. And the Radio Shack online store still has it available 😮

I had a Radio Shack branded tube which I assume was the same stuff as that "Archer" tube. I remember it costing 99 cents for the tube around 99/2000 or so (edit: it's *still* 99cents? Wow). Prior to that time I never used thermal compound at all - I didn't even know it existed. I used that tube so many times the little plastic cap broke into 2 pieces.
Back then I was having heat problems with my K6-3. I was always having heat problems with the K6-3. It's the chip that made me take cooling seriously.
I finally discovered thermal paste on the internet, ran to get some at Radio Shack, and found that adding it dropped the temperature by 5C. But then I got silly. I had also read an idea on some internet forum about filling the outer recessed part of the heatspreader with enough paste to make it flush. A few days ago I was amused to see that my K6-3 still has a lot of the old paste pooled in there. It was completely pointless, it's too deep to transmit any heat.

Nowadays, for an old undemanding PC I would just use whatever is the most worthless tube of compound I have handy. Right now that would be the Cooler Master gray paste that came with one of my heatsinks. It quickly dries into a gray powder, I don't like it at all. I won't use it on any important build, so my only chance to get any use from it is with temporary builds or old CPUs that in my estimation don't really need the paste anyway.

If I was buying something new for money, I'd probably get the Arctic Silver Ceramique. I've been happy with it before and use it on pretty much anything. It's cheaper than the premium stuff, and I remember seeing some specs somewhere that suggested it was a bit more tolerant of suboptimal conditions (rougher surfaces and temperature extremes). I originally made that choice because I was using it on an ignition module in my car, which runs hotter than a PC, but I think it's a good all around paste. A tube lasts forever so I'd just get something I can use for everything, and that I know doesn't dry out too quickly. The last tube I bought also said it was made in USA, so that wins a few points for me.
Maybe for special needs, if I had any, I might get the premium AS stuff, but my catch-all choice to keep in stock is AS Ceramique.

On my test benches I don't use any paste. I swap parts too often and it's too messy as well.

Whenever I'm out of thermal I just go to the store on my street and ask for the cheapest stuff they have. If it's not for cpu I just use 3M doubleface tape

I generally just order the largest Arctic Silver 5 tube that I can get my hands on and then use it for everything I have, old and new. For smaller applications (Chipsets and whatnot) I have recently taken to using a generic thermally conductive glue. This is only used where mounting a heatsink mechanically is impossible as I reason it has to be better than the tape. It seems to be adequate for chipsets, voltage regulators, MOSFETs and amplifiers at any rate.

Since most of the stuff I have is 486 DX4 and earlier, I currently either use the Arctic Silver I've had since I built my Pentium D in 2008, or a stockpile of old Dell tubes I've had from years ago. Though as of late, I've been using thermal pads attached to chipset heat sinks rather than thermal paste, with a good fan that seems to work best even on my 486 DX2/66.

The Arctic Silver mostly is for the Pentium D 3.40GHz, even when I first got I never got that darned thing to run at a good temperature, as Pentium D's generate enough heat to work as a space heater in the winter. The Arctic Silver and ginormous copper cored thermal unit are a part of what keeps that thing running cool enough not to die.

antec nano diamond on everything

Copper paste works good 🤣

Used an AS5 tube for years (don't remember if I bought or got it for free with a cpu cooler in 2005 or so, but it lasted up to last year 😳 ) on all my cpu's (from 486's to my Core i3 2120) 😎