Slow Regeneration on Map5

[Anonymous]

Autodesk Map 5.0 Commercial Product New Licence

I have problem with regeneration during loading 22MB 2D vector drawing file
(part of town - streets and houses), interesting point is that regeneration
is working fine with 256MB rambus, but when I install 512MB or 768MB
regeneration takes twice longer to complete, or even Map hangs up.
I have Win2000Pro SP3 - clean installation, P IV-2GHz,
Intel D850Chipset, ATI Radeon 9000 w 64MB DDR - I tried few versions of ATI
Catalyst drivers(I even tried with ATI Radeon 7000 - same result), 160GB
7200rpm IDE HDD.
Other applications on PC; OfficeXP and Norton AntiVirus v7.5 Corporate

Thanks, Vice