I was trying to figure out why Virtual-T is faster and deactivated the Option ROM wondering if that could have any impact. I was surprised that REX# would affect a running BASIC program at all. Even with an Option ROM activated, REX# still showed a slow down (about 10%) but I didn't investigate that deeply as I don't have a non-REX Option ROM handy to benchmark against.
—b9 On Tue, Feb 10, 2026 at 5:13 PM Stephen Adolph <[email protected]> wrote: > Thanks, this is interesting. > Perhaps I can do something to improve that. > > Having no option rom activated seems like an unusual state. Why do you > have no option rom activated? > > Steve > > On Monday, February 9, 2026, B 9 <[email protected]> wrote: > >> Virtual-T seems to be running too fast for me compared to real hardware >> (Tandy 200). I could be doing things wrong, so it’d be helpful if other >> people checked this out as well. >> >> Experimentally, my Tandy 200 takes 10 seconds to count to 3535. >> >> FOR T=1 TO 3535: NEXT >> >> When I do the same thing on Virtual-T’s emulated T200 it takes only 6 >> seconds. >> Machine Time to count to 3535 >> Genuine T200 10s >> Virtual-T 1.7 T200 6s >> Virtual-T 1.7 M100 5s >> >> Is the same thing true for other folks with real hardware? What about the >> Model 100 and Tandy 102 (or other more esoteric of the Kyotronic kin)? >> >> Second thing: REX# seems to slow my machine down significantly when I do >> not have an Option ROM activated. It is completely repeatable. Is this a >> known issue? I tried using the emulated REX in Virtual T, but I must have >> an old version as it only had REX and REX2 listed, not REX#, and those >> didn’t cause any slowdown. >> Machine and REX# setup Time to count to 3535 >> Genuine T200 with REX# De-installed 10s >> Genuine T200 with REX# Installed, but no Option ROMs activated 16s >> Genuine T200 with REX# Installed and any Option ROM activated 11s >> >> Finally, here’s a program that makes it easy to run timing tests >> repeatedly. >> >> 0 REM Speed Check4 COUNT=3535 ' T200 takes 10s to 35355 PRINT"Counting up >> to";COUNT6 PRINTTIME$10 T1$=TIME$20 FOR T=1 TO COUNT: NEXT30 T2$=TIME$: >> PRINTT2$40 H1$=MID$(T1$,1,2)50 M1$=MID$(T1$,4,2)60 S1$=MID$(T1$,7,2)70 >> H2$=MID$(T2$,1,2)80 M2$=MID$(T2$,4,2)90 S2$=MID$(T2$,7,2)110 >> H2=VAL(H2$):H1=VAL(H1$)120 M2=VAL(M2$):M1=VAL(M1$)130 >> S2=VAL(S2$):S1=VAL(S1$)150 IFS2<S1THENS2=S2+60:M2=M2-1:GOTO 150160 >> IFM2<M1THENM2=M2+60:H2=H2-1:GOTO 160170 IF H2<H1 THEN H2=H2+12: GOTO 120180 >> H=H2-H1: M=M2-M1: S=S2-S1190 PRINT"Ran";COUNT;"loops in";200 >> PRINTUSING"##h##m##s";H;M;S >> >> Please let me know what you find. Thanks all! >> >> —b9 >> >
