BSOD when Rendering or Recording a gameplay

Hello, i've got this problem from long time and i can't solve it,i really,really, appreciate your help .

So i've got this BSOD ( 0x00000124 ) when i render a video file with Sony vegas and when i record a gameplay with Dxtory , that appen frequently but random: sometimes i can render and record fine, sometimes there are many Bsod...

My pc is pretty new i've tried also to bring it back to the seller , they tested the ram and the processor (i think) and update the bios, but nothing... so i formatted the pc and all then seemed to be solved , but then the problem started again... i thought that could be something related to the HDD filled by the big video file ( that i record and render ) so i've tried with an external hdd for the rendering...but nothing.

I don't know what to do , thank you so much for your time.

It is a 0x124 error which is caused by hardware. Normally these are caused by a faulty CPU but other hardware components can cause it. It's mostly likely your GPU failing because it only happens on graphic intensive operations.
Please download and run furmark and run a burnin test by following these instructions.

Video Card - Stress Test with Furmark

Post the results.

Ok, i've tested the GPU with Furmark for 35 minutes but nothing, the temperature was 80 ° stable, 17 fps on 1920 x 1080 resolution , no blue screen, should i test for more time?

No that should be fine. Can you please run Prime95 for an hour to two hours.
Follow these instructions.

Hardware - Stress Test With Prime95

I've runned the test for 2 hours but it doesn't show any error, none blue screen and the temp was around 75 °C

Okay that's good. So we can assume the CPU is not faulty, there is a slight chance that it is faulty but it's very unlikely.
I have encountered 0x124 bugchecks before, in fact I've had them myself and I've found out that they can be caused by drivers, it's very rare but it can happen.

On that note, I would recommend running Driver Verifier to see if drivers are indeed responsible.
Follow these instructions on how to enable it.

Driver Verifier - Enable and Disable

Ok i've added the Drivers not provided from windows, now what will change if i have a blue screen? should i in my case try to render and record gameplay in this 24h to have a blue screen?

Thank you doctor for your great help and support :)

Yes, basically Driver Verifier will cause a BSOD if it finds a driver misbehaving. What will change is what is in the dump files. So it will help us identify the driver(a) causing issues.

You are still getting bugchecks that point to an uncorrectable error.
Can you try and run RAM - Test with Memtest86+

Afterwards, take a look at this.

Stop 0x124 - what it means and what to try

I'm still not sure because it looks like a CPU error.

Code:

*******************************************************************************
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
*******************************************************************************

Use !analyze -v to get detailed debugging information.

BugCheck 124, {0, fffffa8007b24028, be200000, 2110a}

Probably caused by : hardware

Followup: MachineOwner

Code:

===============================================================================
Common Platform Error Record @ fffffa8007b24028
-------------------------------------------------------------------------------
Record Id     : 01cf505764032be5
Severity      : Fatal (1)
Length        : 928
Creator       : Microsoft
Notify Type   : Machine Check Exception
Timestamp     : 4/5/2014 0:39:59
Flags         : 0x00000000

===============================================================================
Section 0     : Processor Generic
-------------------------------------------------------------------------------
Descriptor    @ fffffa8007b240a8
Section       @ fffffa8007b24180
Offset        : 344
Length        : 192
Flags         : 0x00000001 Primary
Severity      : Fatal

Proc. Type    : x86/x64
Instr. Set    : x64
Error Type    : Cache error
Operation     : Generic
Flags         : 0x00
Level         : 2
CPU Version   : 0x00000000000306a9
Processor ID  : 0x0000000000000003