I not sure this is the place to post this, but some have suggested its a hardware issue, while others have not.I've been getting these crashes after about an hour and a half.My system specs are below.I had folks suggest that my memory timings are wrong. They're not. And I've had folks suggest my system is unstable and I should reduce the clock.Howver, I run Prime95 and Intel burn test and no problem. With FSX running my temps (as measured by Real Temp) run between 35c and 50c., which seems OK to me.I've got FSX and the addon aircraft on a 128 SSD and RC, UTX, GEX, UT2, and FSGlobal on my 1T WD.Anybody had any experience with this?Thanks.Dan Cole

The FSX CTD forum is a good place to start.http://forum.avsim.net/topic/323044-atcdll-ctd/page__p__1904731__hl__atcdll__fromsearch__1#entry1904731Sorry, had to edit in the link. I thought I had copied it.

Edited February 16, 201214 yr by ZachLW

DanCan we see what OS you are using plus service packs. eg Win 7 HP SP1 64-bit and is it up to date with the latest dl from MS?If Win 7 or Vista - Have you applied any 'bcedit' tweak to the OS?The 2 dll errors you reported are usually 'non-specific' ie FSX crashes and they just happen to be the modules that are loaded. These types of errors usually (not always) tend to show that the system ran out of Virtual (Process) Address Space and that can be due to very high settings and/or complex add-ons.(An analogy would be that a car crashes into a brick wall and you only blame the car mechanically when it could have been speed, slippery road, bad driving etc.)WRT RAM timings in a SB system you can't really overclock or change the timings because the FSB is fixed and RAM timings are usually linked to the FSB, so if your RAM settings are the BIOS defaults, I can't see them causing an issue. If you changed any RAM parameter in the BIOS then that could cause problems. Have you ever run the 'event viewer' and looked the details when the crashes occurred?With a little more info we may be able to help you.RegardsPeterH

DanCan we see what OS you are using plus service packs. eg Win 7 HP SP1 64-bit and is it up to date with the latest dl from MS?If Win 7 or Vista - Have you applied any 'bcedit' tweak to the OS?The 2 dll errors you reported are usually 'non-specific' ie FSX crashes and they just happen to be the modules that are loaded. These types of errors usually (not always) tend to show that the system ran out of Virtual (Process) Address Space and that can be due to very high settings and/or complex add-ons.(An analogy would be that a car crashes into a brick wall and you only blame the car mechanically when it could have been speed, slippery road, bad driving etc.)WRT RAM timings in a SB system you can't really overclock or change the timings because the FSB is fixed and RAM timings are usually linked to the FSB, so if your RAM settings are the BIOS defaults, I can't see them causing an issue. If you changed any RAM parameter in the BIOS then that could cause problems.Have you ever run the 'event viewer' and looked the details when the crashes occurred?With a little more info we may be able to help you.RegardsPeterH

Here are the crash details:Problem signature: Problem Event Name: APPCRASH Application Name: fsx.exe Application Version: 10.0.61472.0 Application Timestamp: 475e17d3 Fault Module Name: atc.dll Fault Module Version: 10.0.61472.0 Fault Module Timestamp: 475e180e Exception Code: c0000005 Exception Offset: 00028bb1 OS Version: 6.1.7601.2.1.0.768.3 Locale ID: 1033Additional information about the problem: LCID: 1033The OS is Windows7 64-bit with all the latest MS uploads and service packs. Don't know what bcedit means, so I think not.My settings are from Nick N.'s guide, which I thought to be relatively conservative.With regard to the ram settings, I'm not too clear on what you're saying. Following an OCing guide I replace the defaults with the specific setting of my ram: 1600 for the speed and 8,8,8 and 24 for the timings.I am running alot of stuff (AS2012, RC, UT2, UTX, GEX, FSGlobal, NGX, etc.) but figured this system could handle it.Thanks for respondingDan

The C0000005 exception code is a memory access violation trapped by the OS. It's a very common error, and not probably related to any particular piece of software,My experience is that usually these are related to either an unstable overclock or a memory DIMM heading south.I'd suggest first running Memtest 86+ through 10 passes, and then after that, take a look at your overclock.

"Danwrt RAM - what I was saying is for SB that you should use the default settings in the BIOS for all RAM settings as changing these may give rise to similar errors to what you are experiencing. There is no need to oc RAM in a SB rig as it makes no virtually difference to performance.SB is different in that you overclock the cpu multiplier and not the FSB and if you have changed the RAM settings, as you state above, you now may have a mismatch between the FSB and the RAM.Have you tried to use 'fail safe' or 'reset' settings in the BIOS and see if this problem still occurs?Just a thought.PeterH

Edited February 16, 201214 yr by peterhayes

I had the atc.dll errors recently after new build. I set BIOS ram to manual1600, which I assumed was correct and was getting many of the atc,dll errors. I set the BIOS to auto for the timing and in a month havn't had one error? ( I fly 100+ hrs/mo) maybe coincidence? ASUS MB. P8P67PRO, 2600K

Edited February 16, 201214 yr by Barnstormer1

The C0000005 exception code is a memory access violation trapped by the OS. It's a very common error, and not probably related to any particular piece of software,My experience is that usually these are related to either an unstable overclock or a memory DIMM heading south.I'd suggest first running Memtest 86+ through 10 passes, and then after that, take a look at your overclock.

I will run memtest86 and set the timings to default as recommended by another. I do have a question about the clock though--I've run both Prime95 and Intel Burn Test extensively and have no apparent problems. Does that indicate the clock is stable? Thanks.

I had the atc.dll errors recently after new build. I set BIOS ram to manual1600, which I assumed was correct and was getting many of the atc,dll errors. I set the BIOS to auto for the timing and in a month havn't had one error? ( I fly 100+ hrs/mo) maybe coincidence? ASUS MB. P8P67PRO, 2600K

I just had another crash, so I'm going to try setting the BIOS to auto now. Thanks.

I will run memtest86 and set the timings to default as recommended by another. I do have a question about the clock though--I've run both Prime95 and Intel Burn Test extensively and have no apparent problems. Does that indicate the clock is stable? Thanks.

It indicates that the clock is stable for Prime95 and Intel Burn Test. i know a few folks that had the burn-ins running just fine but still had major grief from FSX. I suspect FSX stresses the machine differently, perhaps in how it hits the memory.

I just had another crash, so I'm going to try setting the BIOS to auto now. Thanks.

Rather than auto, I would suggest manually setting the timing specs that came with the RAM. Also, if your mobo allows it, make sure the DIMM voltage isn't drooping to below the rated DIMM voltage.

It indicates that the clock is stable for Prime95 and Intel Burn Test. i know a few folks that had the burn-ins running just fine but still had major grief from FSX. I suspect FSX stresses the machine differently, perhaps in how it hits the memory.Rather than auto, I would suggest manually setting the timing specs that came with the RAM. Also, if your mobo allows it, make sure the DIMM voltage isn't drooping to below the rated DIMM voltage.

That's how I had them set before. Check the DIMM voltage in the BIOS or is there some app to check it while FSX is running.Thanks for your help.Dan

BobSorry but this does not apply to SB:

Rather than auto, I would suggest manually setting the timing specs that came with the RAM. Also, if your mobo allows it, make sure the DIMM voltage isn't drooping to below the rated DIMM voltage

It's better in SB to run with the default RAM settings for the BIOS/mobo as setting them manually can cause a mismatch and that may manifest itself in the errors the OP is experiencing.You are running an i7 9xx which does require tweaking the RAM timings etc because overclocking an i7 9xx involves the FSB and not the cpu multiplier. Changing RAM speed or CAS latency has very little effect on a Sandy Bridge system because you are oc the cpu multiplier only, the FSB stays the same, so changing any RAM setting is fairly counter productive.If you change the RAM settings in a SB rig you are probably likely to see the exception code error at c0000005 because the FSB and RAM timings no longer have a 1:1 relationship and under load a memory exception may occur, possibly because a particular memory address is no longer where it is meant to be.Apologies for disagreeing.RegardsPeterH

I would suggest manually setting the timing specs that came with the RAM

That what I did and had all kinds of atc.dll's until setting to auto. Certainly won't hurt to try it!

Edited February 17, 201214 yr by Barnstormer1

BobSorry but this does not apply to SB:It's better in SB to run with the default RAM settings for the BIOS/mobo as setting them manually can cause a mismatch and that may manifest itself in the errors the OP is experiencing.You are running an i7 9xx which does require tweaking the RAM timings etc because overclocking an i7 9xx involves the FSB and not the cpu multiplier. Changing RAM speed or CAS latency has very little effect on a Sandy Bridge system because you are oc the cpu multiplier only, the FSB stays the same, so changing any RAM setting is fairly counter productive.If you change the RAM settings in a SB rig you are probably likely to see the exception code error at c0000005 because the FSB and RAM timings no longer have a 1:1 relationship and under load a memory exception may occur, possibly because a particular memory address is no longer where it is meant to be.Apologies for disagreeing.RegardsPeterH

Peter--I'm running an i7-975EE which is completely unlocked, and RAM is overclocked with either or both of the BCLK and memory multipliers.On SB, the base clock is not flexible as it is used to set speeds of PCIe and other internal components that become unstable if taken much off their design frequencies. So with BCLK constrained to a fixed value, the RAM speed is set by virtue of a multiplier, hence the fixed speeds of 1333, 1600, 1866, and 2133 commonly in use on SB mobos. Changing the memory mult on an SB rig does not take the RAM out of sych with the IMC, as both the RAM and the IMC run off the same clock. In fact you don't have the ability to make RAM run at a different speed than the IMC on a SB CPU--they are both running off the same physical clock signal.SB is much less sensitive to RAM bandwidth--not because of anything to do with how it's overclocked, but because of the whopping big set-associative L3 cache on the CPU die, which allows keeping most of the code to be executed in the uber-fast CPU cache. All that said, many motherboards, SB included, don't work well with the XMP settings on the DIMM. I always set my RAM timings up manually according to the manufacturer's specs. You can run at "auto" which usually sets the RAM according to the lowest SPD profile, which is generally much slower than the DIMM maker's rated performance specs. But then why pay for 1600 or 1866 MHz RAM at all if you're going to run it at 1333?

That what I did and had all kinds of atc.dll's until setting to auto. Certainly won't hurt to try it!

Nope, won't hurt, just as long as you realize that you're essentially underspeeding your RAM when you do this, which may mean that it's not performing up to its advertised specs.

Nope, won't hurt, just as long as you realize that you're essentially underspeeding your RAM when you do this, which may mean that it's not performing up to its advertised specs.

Memtest86 passed with flying colors.BTW I'm running an I5 2500K not an I7.Let me add a couple of variables to this. Before January, I was getting virtually no CTD's.Two changes were made in January:I added a 128 GB SSD to my configuration and put FSX, addon planes on it. Other softweare such as scenery, UT2, AS2012 and RC are on the 1T WD. Before, all theFSX stuff was on the WD. I installed FSGlobalCould either one of these changes have anything to do with the crashes?Thanks.