Fine tuning on DGX spark vs 4x 3090?

hey, my research direction don’t focus on inference or eval benchmarks. specifically, it’s mech interp research direction, analyzing how models do computation etc

i dont have GPU, mostly using cloud GPUs loaned by third parties. i saved up some scholarship money by spending less each month and now I am considering to own a GPU. 4x 3090 would require electricity beyond normal while DGX spark draw reasonable electricity. the other concern is a 3090 is too old, I can’t afford having dying GPU as student

i am prepared for slower fine-tuning etc but I would like to know exactly how slow compared to 4x 3090 on large models

anyone with experiences are welcomed to share