Does upgrading RAM with different Speed, affect the pc or affect all the RAM?

I have 4gb RAM in my system. I went to shop for upgrade. They told he has different number like "2666" but in my system RAM its number is different. So we need to wait to get exact number for upgrade.

Since its emergency, i went other service centre and changed(with different number "2666" RAM, manufacturer: Crucial). Will it affect my pc?

I read about RAM in google that: Speed, frequency, Latency, Clock Speed, Size matters for RAM.

Below is my RAM details, in that Manufacturer: SK Hynix is the RAM dell already installed in my laptop. Second one is what i upgraded.

pc:~$ sudo dmidecode -t 17
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 3.1 present.

Handle 0x1100, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x1000
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 4096 MB
    Form Factor: SODIMM
    Set: None
    Locator: DIMM A
    Bank Locator: Not Specified
    Type: DDR4
    Type Detail: Synchronous
    Speed: 3200 MT/s
    Manufacturer: SK Hynix
    Serial Number: 215AA823
    Asset Tag: 02202200
    Part Number: HMA851S6DR8N-XN    
    Rank: 1
    Configured Memory Speed: 2667 MT/s
    Minimum Voltage: Unknown
    Maximum Voltage: Unknown
    Configured Voltage: 1.2 V

Handle 0x1101, DMI type 17, 40 bytes
Memory Device
    Array Handle: 0x1000
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 8192 MB
    Form Factor: SODIMM
    Set: None
    Locator: DIMM B
    Bank Locator: Not Specified
    Type: DDR4
    Type Detail: Synchronous
    Speed: 2667 MT/s
    Manufacturer: 859B
    Serial Number: E56992CC
    Asset Tag: 1A213100
    Part Number: CB9GS2666.C8JT      
    Rank: 1
    Configured Memory Speed: 2667 MT/s
    Minimum Voltage: Unknown
    Maximum Voltage: Unknown
    Configured Voltage: 1.2 V

From my above details, i can see that Speed is different(default: 3200 MT/s, newOne: 2667 MT/s). I googled and came to know that

If you install two RAM sticks of different frequencies, both of them will be working on the lowest frequency. So, if you Installed one stick with 1600Mhz and other with 2400Mhz, the latter will work on 1600Mhz, thus lowering its efficiency.

In my case i have installed lower speed, So will it make the RAM(2667 MT/s) to work on 3200 MT/s speed.Will my system pressure it? Does it cause damage to my system or default RAM or new RAM?

And Locator, Serial Number, Asset Tag, Part Number are also different.

Thanks!

As long as the RAM is working and being recognized by your motherboard, the faster chip will run at the same speed as the slower chip. Since the slower chip is what speed you were already running at, you wouldn't see a performance decrease. You just are not getting the advantage of the higher clock speed of the new faster RAM.

It will not damage your system or the RAM.

The other issue is the mismatch memory size will affect your Dual-Channel memory performance. This won't be any worse than what you had before adding the extra RAM, you just are not taking advantage of the full potential of your memory and your CPU - see this https://serverfault.com/questions/912283/can-mixing-ram-memory-size-on-its-own-reduce-dual-channel-performance/912298

One other factor you should consider is that subtle differences between mismatched RAM can cause system stability issues and crashing. This may not be obvious at first and you might only discover these crashes while the system is being used under load.

All of the above reasons are why you should use identical sticks of RAM of identical size whenever possible.