I just have a question if on an rMBP if I download a lot of Torrent does it cause any harm to the Hardware of the Device ? Can too much downloading pose any harm to the machine ?
Here's one way to access / monitor the SMART info of the SSD:
Install the Homebrew package manager by typing the following into terminal (simply cut and paste into terminal):
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install
Once installed, you can type "brew doctor" in terminal to confirm everything is working (it will return "Your system is ready to brew" if there aren't any problems, or might ask you to run another command to resolve something).
You can then use Homebrew to install smartmontools (simply type "brew install smartmontools" into terminal), which provides you with utilities to control / monitor the storage systems on your computer.
Once installed, you simply run "smartctl -a disk0" (which should be your primary disk) to see a printout of your SSD's SMART / health info:
SMART Attributes Data Structure revision number: 40
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x001a 200 200 000 Old_age Always - 0
5 Reallocated_Sector_Ct 0x0033 100 100 000 Pre-fail Always - 0
9 Power_On_Hours 0x0032 099 099 000 Old_age Always - 3385
12 Power_Cycle_Count 0x0032 092 092 000 Old_age Always - 7434
169 Unknown_Attribute 0x0013 253 253 010 Pre-fail Always - 3647115107840
173 Wear_Leveling_Count 0x0032 193 193 100 Old_age Always - 81618993212
174 Host_Reads_MiB 0x0022 099 099 000 Old_age Always - 4158947
175 Host_Writes_MiB 0x0022 099 099 000 Old_age Always - 7045400
192 Power-Off_Retract_Count 0x0012 099 099 000 Old_age Always - 1683
194 Temperature_Celsius 0x0022 066 066 000 Old_age Always - 34 (Min/Max 21/65)
197 Current_Pending_Sector 0x0022 100 100 000 Old_age Always - 0
199 UDMA_CRC_Error_Count 0x001a 200 200 000 Old_age Always - 0
240 Unknown_SSD_Attribute 0x0022 100 100 000 Old_age Always - 0
In particular, you can look at "Host_Writes_MiB" and the value associated with it (which I believe represents a health percentage, based on the manufacturer specs).
For example, the Host Writes shown above are 7045400 MiB, which is a little under 7 TB of writes. To put that into perspective, most consumer SSDs I've seen have a specified endurance of 50 to 150 TB.
There was an article awhile back where they actually put SSD endurance to the test, which found the manufacturer ratings to be extremely, extremely conservative. I don't remember the exact numbers, but they were getting up into petabytes (1 petabyte = ~1,000 terabytes = ~1,000,000 gigabytes) of 24/7 writes before the SSDs actually died.
Point being, in all practicality, it's just not something you need to worry about.