What will be the speed of the HDD 7200 RPM through the SlimSata interface?

Question

Hard disks

Welcome all. The following situation arose (sorry for the long introduction to the essence of the issue):
There is an Acer Aspire 5755G laptop with the HM65 chipset, which, according to Intela specifications, has both Sata 3.0 and Sata 2.0 controllers. In the laptop, in place of the HDD, a KINGSTON SH103S3120G SSD with a Sata 3.0 interface is installed - it works at a speed of 400-420 MB / s, as it should be. In place of the CD-ROM, a Hitachi HTS547575A9E384 HDD (Sata 2.0, 5400 RPM) is inserted using a 2nd HDD Hard Drive Caddy Adapter - its speed, according to CrystalMark, is an average of 80 MB / s. Unfortunately, I do not remember how much it gave out when installed in its native slot via Sata 2.0.
Recently thinking about buying a WD Black 750 GB 7200 RPM with SATA 3.0 connector to install it instead of Hitachi. I saw screenshots of CrystalMark, on which Black gave out 120 MB / s. Actually, the question itself:
Will the speed (mainly reading) of the WD Black HDD connected via the SlimSata interface (used in the CD-ROM) increase, or will it be like "exchanging an awl for soap"? That is, does it make sense to install Hitachi 7200 WD Black instead of 5200 RPM? I don't ask about the use of Sata 3.0, because, in my opinion, everything will rest on SlimSata, right?
Thanks to everyone who read to the end and tried to help me with the choice.

Answer 1

For CD-Rom, only a physically different connector. (and then, emnip, only the power connector, the interface one is even physically the same) The logical SATA is the same. Therefore, there should be no difference between the standard installation and instead of cd-rom.
On the interface, you don’t even overlap SATA1 (150mb / s), so SATA2 or SATA3 doesn’t make any difference.
7200rpm will be faster than 5400rpm due to physics. But the heating is also higher (which in a place not intended for placing the HDD can be very unpleasant for the disk) and power consumption. Will it be much faster - look for comparisons and reviews. Look at the tests in the conditions you need and decide if it's worth it.