Slow Post/Boot on IBM 8187

A Lenovo/IBM 8187 M50 ThinkCentre desktop is slow to boot. Once power is applied, it takes about 30 seconds for the IBM logo to appear in POST. Then, the "press F1" prompt stays on the screen for 20 to 30 seconds. The BIOS is the latest one, and the CMOS battery is good. The problem persists with the floppy and CDROM disconnected. The same slow performance existed when the computer had 512 MB memory, and it exists now that I have upgraded it to 2 GB using different modules, thereby eliminating memory as a problem. The only other peripheral is the hard disk, which passes Seatools long test. The boot.ini file is set for 5 seconds on each of two prompts, but I don't think that file is read until the computer is ready to start Windows XP. Any ideas?

Did you checked the BIOS for the enabling the quick boot option? If not then first enable the quick boot from then BIOS and the see whether the issue is still there or got resolved. As the IBM always runs a memtest while booting to check the system performance.So try this out and see whether it is working for you or not.