Helm,
A few points:
(1) Win98 SE does not support more than 512Mb. On my last system from 2002 with 1024Mb of RAM, I had it set up dual boot (multi-partitions) Win98 SE and Win XP Pro. I had to modify, I believe, the vcache parameters in the SYSTEM.INI to get Win98 SE to boot. I had to hide the extra memory.
(2) The sweet spot for Win98 SE was 256Mb of RAM.
(3) The sweet spot for Win XP is 1024Mb of RAM.
(4) My guess would be that Vista's sweet spot would be around 2Gb or more as it has a much bigger footprint than XP.
(5) For the same hardware platform Vista delivers less performance without delivering additional features that make the performance drop a worthwhile tradeoff. The same was not true of 98 and XP. 98 delivered generally snappier response on less hardware than XP, but XP provided for greater stability and much greater concurrency. Besides 98's memory limit of 0.5Gb, 98 was limited in concurrency due to its small heap size and GDI architecture. Now, when comparing XP and Vista, Vista adds little in terms of features. I think the biggest argument is for a better security architecture with Vista, but at this time XP is more mature than Vista. Also, whether it is XP or Vista, most serious security solutions revolve around third party products in either case.
(6) If you stay in the realm of 32 bit, you are pretty much capped taking advantage of physical memory beyond 3Gb. Running Vista means less of that will be dedicated towards applications and games and more for the O/S.
(7) Neither XP nor Vista make good use of today's multi-core CPUs. Neither operating system is capable of dynamically load balancing a set of running processes and threads.
(8) I plan to run XP until 2014 when it will official be dessupported. I recently got a new machine, I made sure to order it with XP.
(9) I think Vista is ultimately going to be for the NT Kernel family what Windows ME was to the 9x family ... a poor stepping stone between the old to the new which had few redeeming qualities.
(10) Here is Gate's himself having trouble containing his criticism of Vista.
http://gizmodo.com/342920/holy-crap-...ws-sucks?%21??