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500MB VAS reduction and increase FPS by 22% in V3 ... need some testers

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I'm looking for some volunteers that know how to do repeatable identical scenario testing ... the claim is that HT OFF will save 500MB VAS and increase FPS


As you know I'm extremely skeptical about "magic bullets" and have explored many of them over the last decade ... however, this "finding" came to me from Saul (LM moderator using the same CPU I have) who was reading a post by Aviator1979 here: http://www.prepar3d.com/forum/viewtopic.php?f=6312&t=114987


Since I had just done some VAS testing earlier in and around Aerosoft's EGLL, I thought I'd put the HT OFF claim to the test.  To my surprise I was able to confirm the 500MB VAS savings and a 22% FPS increase.


Here is the scenario I used:

Prepar3D V3

Aerosoft Heathrow (EGLL)
Orbx FTX Global 
Orbx OpenLC EU
PILOT's FS Global 2010 FTX Edtion Mesh
FSDT GSX ground services (active)
Active Sky Next (ASN) Weather Engine (Archive weather 10/18/2015) 
Majestic Dash-8 Q400
MyTraffic 6 - 2015 schedule
GoFlight Interface Tool
CPU used: 5960X
Do NOT use any affinity tweaks (temporarily remove them if you have them).
Departing gate 108 at EGLL - 11:17 AM - Take note of VAS
Taxi to runway 09L (departing east)
Take off and climb to 20,000 FT - DTO to MEDWY
At MEDWY, come back to PILOK then D113B for landing
(if you miss approach just come back around and land on 09L)
Park at Gate 188 or 186
Shutdown and evoke GSX deboarding - Take note of VAS
If you have FRAPS then log time frame data to file
Run this scenario with HT ON and then again with HT OFF and report back and be sure to indicate what type of CPU you have.
I'll post my video's with my findings tomorrow (uploading them now), but would like to hear from others.
Cheers, Rob.

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I personally get the exact same performance with or without HT on a 6700k. Haven't test how it handles VAS though.

UKPZTGY.png sig_FSL-By-Wire.jpg

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I don't have all that stuff but I saved up a nasty flight with the Carenado Navajo from Renton, WA over the top of KSEA at 2000' MSL, up to the Space Needle and then over to WA05 Apex Airpark. FTX PNW is installed and NA active in FTX Central. I saved ASN weather along with the flight initially but didn't run ASN for the actual test. Heavy overcast conditions and I have all my sliders/shadows/stuff adjusted to "ridiculous", identical settings for each test. I think I'm even getting double freeway traffic from UTX v2 and PNW combined, need to investigate that further but left it as is for the tests. For all intents and purposes "unflyable" for anything other than testing, lol. No AM in the .cfg either time.

First test from a cold boot with HT on FSUIPC.log says:

928035 Sim stopped: average frame rate for last 855 secs = 10.6 fps
942137 === NOTE: not calling SimConnect_Close ...
943136 System time = 18/10/2015 23:45:01, Simulator time = 08:07:10 (15:07Z)
943136 *** FSUIPC log file being closed
Minimum frame rate was 7.2 fps, Maximum was 17.5 fps
Minimum available memory recorded was 993Mb
Average frame rate for running time of 855 secs = 10.6 fps


Reboot with HT off:

979265 Sim stopped: average frame rate for last 894 secs = 10.8 fps
993149 === NOTE: not calling SimConnect_Close ...
994148 System time = 19/10/2015 00:06:21, Simulator time = 08:07:49 (15:07Z)
994148 *** FSUIPC log file being closed
Minimum frame rate was 7.5 fps, Maximum was 19.8 fps
Minimum available memory recorded was 1183Mb
Average frame rate for running time of 894 secs = 10.8 fps

...so I didn't notice much difference in FPS but if "Minimum available memory recorded" is the same as "closest I came to an OOM" then it looks like HT off may have helped somewhat.

i7 2600K @ 4.4, GTX770 4Gb, 8Gb DDR3@1866mHz


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I can't give any scientific results but I definitely get better fps with HT off on my 4790k. I can't comment on the vas though.

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Hi Rob,


Only have FTXG and ASN installed, the rest is default


Used your settings, ironically have been doing all my own testing at EGLL.


Turned HT off and set my 4K monitor refresh to 30htz ? ....... assume that's what you meant?


I was clocking in at 2500 VAS before, using your test it dropped to between 2200 & 2250 VAS (used cloudy settings to test)


cheers Dave


ps frame rates were around 30fps using unlimited, the odd drop to 27fps


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Hi Rob,


i dont have some of your add ons. But did a test flight from Cielosim KPAO over ORBX KSQL to KSFO HD + FTX NCA active in the A2A C 182. In V2.5 an OOM was guaranteed in v3 not close to. My settings are a bit lower than yours but can do that flight with your settings again.




My youtube blog________________________Prepar3D v2.5/v3


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I did a similar test last week.


Can confirm that HT OFF gives more FPS on a 4790k @ 4.5 GHz (unlimited, no AM). And of course much lower temps.


Chris Keller

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HT off gives me around 1-2 fps more on my I7 4790k @4.5GHz, but my VAS didn't change.

Greetings from the 737 flightdeck!

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So oveoclock headroom increases with HTC off....interesting find for sure.

The only reason you can OC more with HT off is less heat. HT on gives more heat so you reach your OC limit a bit sooner. HT on keeps the CPU a bit cooler and so you can OC a bit more. There is no magic headroom here.


I always have HT on and will do my testflights asap, mainly for FPS testing: I don't have any VAS heavy addons so I won't be able to reproduce Rob's test in any way.



Personal test on i7 4790K @4.5 with GTX 780 6 GB on Windows 10. Flying in default Bonanza, above Manhattan on AP, FTX Global, view looking slightly sideways. Fps at unlimited. With HT average between 24.7 and 26.7, without HT average 29.9. VAS didn't change much. So there is a small gain in fps, some 10%. However... performance seemed a little bit choppier without HT. Obviously this is hard to test because micro pauses are always there when looking sideways but I had the impression it was worse without HT.


Obviously this isn't a very hard stress test but it does bring fps down on my PC and it's a flight I can reproduce exactly everytime. I would have to do some more test to see if HT off really is choppier but for now I see no reason to keep it turned off.

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Sorry to say this forum controls really suck, cant figure out how to cut and paste link.


In any case tool used for checking VAS is called ProcessExplorer


You need Science degree to figure out how to use the controls on the forum, would pasted you download link

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