Question about RME latency vs Performance

[DaveS]

I'm looking to get the best performance out of an older 3ghz machine which is using two RME Hammerfal 9652 cards (non DSP). Looking thru the FAQ's on RME's site said that to get the lowest latency out of these cards that you should set Processor Scheduling (under Performance settings - advanced) to background services.

However, having gone thru Bob's Win XP tweaks he is saying to set the scheduling to Programs.

Any thoughts as to which would be a better course of action? Bob - obviously you found that setting the scheduling to Programs was advantageous...is there any validity to what the RME site says?

[Bob L]

In SAWStudio and SAC you want to keep the apps threads ontop... as much as possible or the mix buffers will not be able to handle all the data processing in time... so do as I mentioned in the tweaks doc.

RME is attempting to keep the driver (in the background) from being stepped on... but with the way my code is written, this does not seem to be a problem at all... and you definitely want to keep my threads from being interrupted.

But... you may want to try for yourself both methods and see which gives you better performance under load on your system.

Bob L

[DaveS]

Thanks Bob! I will use your tried and true method. I know you use(d) the same cards.

On a simlar note - I noticed that in the process listings if you check the Processes in Task manager and look at the one for the sound card - Digi96 in my case - you can set the priority for them. Currently my cards are set for normal. Do you think that popping these up a notch or two (not quite to realtime) would provide an improvement?

[Bob L]

You can't run everything at higher priority or you defeat the purpose... but you can experiment and see what works best.

Generally if SS or SAC is at the highest priority, it will do what it needs to keep everything running smoothly.

Bob L

[DaveS]

Agreed - the computer can only do so much in realtime... I was thinking of bumping the soundcard drive up to 'Above Normal' though. there is another step called Higher which I think would start to effect the Realtime settings..

With the Saw-SAC link enabled, should I just leave Saw set to Normal or would it be better to bump it up a notch or two?

[Bob L]

I am taking care of priorities within SAWStudio when the SAC-Link is established... it is very important to leave them alone so the internal engine threads work in precision.

Bob L

[DaveS]

Soooo - in Saw-Sac should I set SawStudio to 'Force Realtime' as well in it's options menu or just let it be 'normal'?

[Naturally Digital]

Soooo - in Saw-Sac should I set SawStudio to 'Force Realtime' as well in it's options menu or just let it be 'normal'?I think you'll notice that when the SAW-SAC link is active, the option will be greyed out in SAW.

[DaveS]

I think you'll notice that when the SAW-SAC link is active, the option will be greyed out in SAW.

Yep - you're right. Excellent! One less decision to have to make! :)

[Bob L]

SAC takes charge of the SAWStudio threads when the link is activated... just leave SS alone.

Set SAC to Realtime priority if that works fine on your machine.

Bob L

[DaveS]

I was running it this evening - about 4 hours - and I got 5 dropped buffers running SAC and SS. It would have been nice to have 0 but I think I probably could get away with that. And more then likely I'll be re-setting it between sets.

Bob - I am assuming I should be using the 24bit WDM driver for SS while SAC runs ASIO? I have noticed something a little strange though - I thought that when you selected a driver in SS that it was only one driver... In mine when I have 24 Bit WDM selected I also have Standard MultiMedia selected. I have to select ASIO - then go back and deselect 24 bit, then go back in and re-select 24 bit for it to be the only one coming up.... I wonder if this is related to that other issue with SAC's Live indicator...

[Bob L]

No... the WDM compatibility is an added option to one of the MME driver modes.

But... when you use the SAC-Link, the driver mode in SS is bypassed anyway... in fact, you can use a preference that leaves all device in and out driver selections at none in SS... SAC handles all the device driver code.

Bob L

[DaveS]

That's good - I was going to ask about that...

So, is there a need/want/desire to set it's buffers or is that also completely taken care of by SAC? When I have left it set for ASIO and had some i/o assignments made, when I would activate the SAC-SAW link it would show the sme buffer setting in SAW as was in SAC. And it seemed that you couldn't make any changes.

[DominicPerry]

That's good - I was going to ask about that...

So, is there a need/want/desire to set it's buffers or is that also completely taken care of by SAC? When I have left it set for ASIO and had some i/o assignments made, when I would activate the SAC-SAW link it would show the sme buffer setting in SAW as was in SAC. And it seemed that you couldn't make any changes.

Dave,

You don't need to set anything and you can't set anything. It's an internal hook between SAC and SAW which handles everything. Stop worrrying :D.

Dominic

[Bob L]

Stop worrying about it... SAC handles all the necessary internal driver settings and thread priorities in order to keep things humming along smoothly when the link is active.

SAW's buffer sizes are set to an internal high setting so it relaxes in the background and does not get in the way of SAC which is responsible for the live latency issues.

At this point, the only thing you should do is manually turn OFF the SAW monitoring options... I wioll probably handle that internally also in a future update.

Bob L

[DaveS]

Ok, Ok, I'll stop worrying! :o

I was just trying to remember some of the various threads regarding buffer settings and such...and wanted to get it straight in my head.
It's done. :)

Thank all of you for your support and replies! My other system worked fine on live gigs...I've just been a bit concerned about this new 'old' system.