GC alloc Spikes with Task.Factory.StartNew()?

I am working on a project requiring alot of asyncronized processing. I need to process colormaps as often as posible but it is not possible to complete within an Update within a reasonable amount of time so I leave that work to threads to complete.

My issue is, I have tried <new Thread().Start()> and <Task.Factory.StartNew>. In all the forums I read, Tasks are prefered over Threads, however, in my particular case, using Tasks causes GCalloc spikes much often than Threads. Is this to be expected? How can I remedy the situation?

Please find the code and resulting profiler screens below;

Using Tasks;

Code (CSharp):

1. void Update()
2.     {
3. if (is_completed)
4. {
5.                     t_mainCameraTransform = Camera.main.transform;
6.                     Task.Factory.StartNew(GenerateAtmosphereColorMap, t_mainCameraTransform.position);
7.                     Task.Factory.StartNew(GenerateLithosphereColorMap, t_mainCameraTransform.position);
8.                     Task.Factory.StartNew(GenerateAquasphereColorMap, t_mainCameraTransform.position);
9. }
10. }

Profiler: GCalloc in about 100 frames


Using Threads;

Code (CSharp):

1. void Update()
2.     {
3. if (is_completed)
4. {
5.                     t_mainCameraTransform = Camera.main.transform;
6.                     new Thread(new ParameterizedThreadStart(GenerateLithosphereColorMap)).Start(t_mainCameraTransform.position);
7.                     new Thread(new ParameterizedThreadStart(GenerateAtmosphereColorMap)).Start(t_mainCameraTransform.position);
8.                     new Thread(new ParameterizedThreadStart(GenerateAquasphereColorMap)).Start(t_mainCameraTransform.position);
9. }
10. }

Profiler: