Hmm, I tried normal mame64.exe and it still ran at 85%, even on an LCD
So do you mean that base line MAME also runs wbml at 85%? There's something really odd going on there. Have you tried it in the same folder where GroovyMAME is or created a new one? I'm wondering if any old config file in the ./cfg folder could be causing issues...
It's totally weird. I tried the same mame folder, with same config, etc on a different PC and wbml runs at 100%.
I tried a brand new mame folder on my groovymame machine, extracted straight from the official mame archive and wbml still runs at 85%. Street Fighter II runs at 100% as well as pretty much everything else I've tried, so I'd be surprised if my PC couldn't handle wboy and wbml. I am tempted to try installing official Radeon drivers to see if it's CRT emudriver causing the issue but I'm worried it'll be a pain to get it installed again.
Just tried some other games that I thought might be troublesome and it's the vertical games like commando, 1942, pacmania. Pacmania runs at around 85% without triplebuffer and multithreading and commando and 1942 run at 97%. I think the arcade refresh is 60hz and it's selecting 58.48 for me. Does that mean the mode selection can't find a modeline at the right refresh for me? I'm not really sure how the mode generation and selection works, I've done a lot of reading but still a bit confused. If I run the vertical games with the orientation set to vertical they all run at 100%. wbml and wboy are still baffling though.
Also, is there a setting that makes the vertical games auto rotate rather than having to set the orientation switch each time? I have a small CRT here that I can easily turn on its side for vertical games. I've tried playing with the rotate option in the ini, setting it to 0 and 1, chaging autorol and autoror but nothing works. If I set -norotate, -autorol or -autror from the command line it works but I'd rather have it in the ini. It looks like switchres is overriding what I have in the core rotation options of the mame.ini. The rotation options in the ini work fine if I use a vanilla mame with no switchres settings in the ini
Edit: So it looks like an i7-930 at 2.9 Ghz isn't fast enough for some games, I can kind of understand it only running Street Fighter EX2 at 60% with no multithreading (I can get it up to 86% turning multithreading on. I can't understand why Wonderboy in Monsterland won't run at 100%, even with MT on it only runs at 92%. I thought a P4 would have been fast enough for wbml, I'm sure I was running it years ago with no problems. I installed the latest official Catalyst and it didn't help, so nothing to do with crt_emudriver or groovymame

Maybe XP 64 performs poorly? I tried disabling hyperthreading my bios too to make sure it wasn't causing anything funny, but not joy.
My i7-4770k running Windows 8.1 is running everything I throw at it at 100%

I wanted a dedicated groovymame machine though

Just did a quick test on wbml with -nothrottle. It runs at 82% on my i7-930 and 1300% on my i7-4770k, is my 4770k really 15x faster? I wouldn't have thought so

I did the same test with -mt on and my i7-930 ran at 873% (more like it) and the i7-4770k at 1473%, so why on earth is throttling bringing it down under 100% on the i7-930? Argh, tearing my hair out over this, been messing with it all day!

It has to be an XP x64 thing.
Another edit:
I'm convinced that xp64 just plain sucks. Tried standard mame64 on a windows 7 x64 machine with a Q6600 and 4GB ram and everything is running at 100%, even sfex2, this is without -mt on. So if my ancient Q6600 can run this games fine then surely my much newer i7-930 can. I installed xp x64 because the groovymame guide I followed recommended it! Can't believe how much time I have wasted on this crap! I think I might just use xp32 on my Q6600 for groovymame and be done with and install an operating system on the i7-930 that it deserves

It's a real shame we can't use windows 7 for crt_emudriver
