THE PIII processor conflict

[Mack1982]

While searching for a PIII 500MHZ processor for my proliant 800, I came across two different kind of 500mhz processors,...
1) INTEL/PENTIUM 3/500/100/512 S2

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=5746914762&ssPageName=STRK:MEWN:IT


2) 500/512/100/2.0V S1

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=14292&item=6740522659&rd=1

Now, I can understand all the description except for the "S1" and "S2" part. What does that mean,...

I found this on the net,...

100MHZ FRONT SIDE BUS 512KB LEVEL-2 CACHE SECC-2

Does the S2 stand for SECC-2
and S1 for SECC-1

here is the link:
http://www.sparepartswarehouse.com/Compaq,Server,Part,114525001.aspx

 

[Praetor]

S1 and S2 stand for stepping1 and stepping2
The SECC is the packaging form (i.e., cartidge)

 

[Mack1982]

Can you elaborate on that a little bit. What does that mean "stepping 1" and "stepping2"? Does that make a difference which one is it, in order to work in my proliant?