I don't see the sense of replacing one old-bad-cheap socket for another ?
The sockets used on arcade boards I've seen so far are of the cheap kind:
Those make contact to the IC pins using "pressure", much like a PCB edge connector does. They also use lesser quality metal. So why did they use them ? Well, they were fine for as long for the games expected life-time in arcades, 2-3 years and they were cheap !
We all know they can oxidize but even worse, they loose contact because of the "pressure" is getting weaker when they get old. (Like a spring loosing it's tension).
When I replace IC sockets I _ALWAYS_ use sockets with wound contacts. You can recognize them by the circular shaped holes:
Inside of the holes, the metal contacting the IC leg is wound like a spiral. This way it has LOADS of contact with the leg. They do not rely on a "spring" tension so they cannot loose it and they are usually made of better quality metals.
Needless to say they are (much) more expensive. It's not too bad if you need a couple of sockets, but it really adds up if you need large numbers. Often the IC's I use in those sockets are cheaper than the sockets themselves.
Still, I would never use anything else.
You should really try to remove an IC from a cheap socket and then from the same socket in "wound" version..... You can _feel_ that it's better, it has a very firm grip on the chip.
The numbers you mention (the one's after the -) are an indication of the possible speed of the RAM IC.
The lower the number, the higher speed it can handle. However, I've replaced RAMs on my SW that were -10 with new versions that are -15 without any problem. It just depends on how fast the memory is accessed by the system in which it's running.
Also: if you insert a "faster" chip, the board will NOT run faster because the memory is still accessed at the same frequency.
I remember some service bulletins from Atari telling not to use certain brand of RAMs but I can't remember what brand...Think it was in the Arcade Archives somewhere...