Replaced Motherboard By Intel Under Warranty Performing Way Below Than The Original One I Send For RMA.Any Solutions Please?

Ok i am new here.I have an intel i7 860 2.80 ghz processor which came bundled with the dh55hc motherboard.it all seems to be working fine for 2 years but recently some major problems occured.The processor seems to overheat quite a lot (although i never ever overcloked,i am not an overclocker by any means)and later it failed to boot up the system.So i went to intel service center and made an RMA and they replaced me with a new boxed processor of exactly the same model.The new processor was working fine with my old motherboard.But since i was having some minor issues with my motherboard too like the motherboard became a little bit flexible(i mean i was able to bend it a lil bit),lan was not working properly and all the ram slots were not wroking etc.,so i thought lets make an RMA for the board too since it was under warranty too.As usual,after the RMA,intel replaced my old motherboard With wxactly the same model i.e.DH55HC but from the moment i opened the pack,i had some doubts that the motherboard provided to me is a refurbished one or a repaired one,its defenitely not a new one,as intel send it without original packaging in a brown box.And my doubts confirmed when i opened the pack and when properly checked,i found some dust particles on the board which can happen only in an old board which is repaired or refurbished.But it was absolutely fine for me till i installed the cpu to the socket and mounted the the intel stock cooler with the thermal paste provided by intel in the box.as soon as i boot my pc,right from the boot screen i can find significant difference i.e.the intel welcome screen is taking time to load and after i login to windows,the overall system performance was horrible when compared to my old motherboard,everything was working much slower than my old motherboard,so i contacted intel and they advised me to format and re-install the windows along with all the drivers and they said the motherboard will perform just like my old one after formatting and re-installing drivers.So i did exactly what they instructed,formatted the windows and re-install the drivers with the latest drivers provided in intel website for this particular board.But even after doing all these,still i can see relatively slower performance of the motherboard.i have tested the motherboard temperature with many testing softwares and it reads 40 c at startup and keeps on varying i mean increasing,no sign of decrease.my original board use to give 34c (almost static) and never increased after 5-6 hours of usage constantly.Things i want to mention,i am using the same psu,ram and every specs all the same.I have already asked intel to send my original motherboard back to me and take away this crap bullshit they have provided and not to send me any replacement board.My questions are will intel provide me the same board i send to them for RMA?Is the rise in motherboard temperature and overall speed difference means the motherboard they replaced is faulty?Shall i get my original motherboard back or ask for another replacement?does this replaced board will last long than my old motherboard?Does slow welcome screen loading means there is some fault with the motherboard?There are many other questions which are coming to my mind now but i want atleast these things to be cleared for me by an expert.many many thanx in advance if you solve my issue with some simple and comprehensive answers.with best regards,Subhamoy Halder.