Question Could someone explain the difference between PCI and PCI-E?

Apr 19, 2021
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I have two PCI-E ports and two PCI ports. I heard that PCI-E ports are apparently significantly faster. Does this mean that using a PCI port will bottleneck my RAM.

I have one stick of 8GB 1600mhz RAM which is currently inserted into one of the PCI-E ports. I am thinking of buying an additional two sticks of 4 GB 1600mhz RAM, however, I only have one more PCI-E slots. Would using a PCI slot for my last piece of RAM bottleneck my memory?
 
You seem to be confused, RAM and PCIe / PCI use entirely different lanes and low level communication. Bottlenecking your PCIe slots will not affect your RAM in any way, RAM have their own dedicated link to the CPU. As for PCIe vs PCI, PCI is a relatively old interface that's not commonly used anymore, if you're buying a modern component like an NVME SSD, a GPU, or other PCIe device, it will most likely use your PCIe slots and not the PCI.
 
Apr 19, 2021
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You seem to be confused, RAM and PCIe / PCI use entirely different lanes and low level communication. Bottlenecking your PCIe slots will not affect your RAM in any way, RAM have their own dedicated link to the CPU. As for PCIe vs PCI, PCI is a relatively old interface that's not commonly used anymore, if you're buying a modern component like an NVME SSD, a GPU, or other PCIe device, it will most likely use your PCIe slots and not the PCI.
Ok, so to clarify, can I use either PCI-E or PCI for my RAM and it wouldn't negatively impact my PC performance? Or does RAM connect to the motherboard via an entirely different type of connection? I apologize for me sounding stupid, I am very new to this kind of stuff.

Right now I have an ASUS H87M-PLUS motherboard (not in a complete computer) with an 8GB 1600mhz stick of RAM in one of the ports. I guess I'm not entirely sure which port I plugged it into.

With my motherboard, do you know if it is compatible to have the following exansions:
1 x 8GB 1600mhz
2 x 4GB 1600mhz
1 x Radeon RX 550
1 x (Some form of internal Wi-Fi adapter?)

Or would there not be enough room for all of these components? In particular, I think most internal Wi-Fi adapters use "PCIe x 1" or "PCIe x 2" slots and I'm not sure what those are. All I know is that they are very small.
 
Ok, so to clarify, can I use either PCI-E or PCI for my RAM and it wouldn't negatively impact my PC performance? Or does RAM connect to the motherboard via an entirely different type of connection? I apologize for me sounding stupid, I am very new to this kind of stuff.

Right now I have an ASUS H87M-PLUS motherboard (not in a complete computer) with an 8GB 1600mhz stick of RAM in one of the ports. I guess I'm not entirely sure which port I plugged it into.

With my motherboard, do you know if it is compatible to have the following exansions:
1 x 8GB 1600mhz
2 x 4GB 1600mhz
1 x Radeon RX 550
1 x (Some form of internal Wi-Fi adapter?)

Or would there not be enough room for all of these components? In particular, I think most internal Wi-Fi adapters use "PCIe x 1" or "PCIe x 2" slots and I'm not sure what those are. All I know is that they are very small.
RAM does NOT use PCIe, it has its own connection, you see the 4 slots bunched up together where your current RAM is installed? That's the RAM slots, they're called DIMM slots (Dual in-line memory module).
Your RX 550 GPU will use your PCIe. RAM and PCIe do not affect each other, they have their own lanes/communication to the CPU and the CPU controls all the the data going to it.

If you already have an 8GB 1600MHz RAM stick installed, then it would be best to get another single 8GB 1600MHz stick, preferably one of the same exact model, though not mandatory. When upgrading RAM it's best to have pairs instead of lone or uneven set of sticks, this is because dual RAM sticks utilize what's called dual-channel memory, this is when the CPU utilizes both RAM sticks evenly and efficiently. Having 1 or 3 RAM sticks disrupts this even distribution and can slow down performance. So thus get a single 8GB stick for upgrading RAM since you already have an 8GB stick.

Also read your motherboard's manual to determine which DIMM slots to install your RAM sticks, you can't just install them next to each other, your manual will tell you which slots are best to install them in. But if you're confused just install 1 RAM into slot 2 (the second RAM slot furthest away from your CPU) and slot 4 (4th slot furthest away, the last one). This will utilize dual-channel. Should look something like this.
 
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mamasan2000

Distinguished
Before PCI-Express, we had AGP for graphics cards. Before that we had PCI for GPUs. So PCI is old and slow, only good for soundcards and NICs. At least it was 5+ years ago. PCI is phased out in just about every motherboard from the past 3-5 years.

https://www.manualsdir.com/manuals/300731/22/asus-p7p55d-pro-page22.png
RAM connects straight to CPU. On the rightside of CPU in the pic. The 4 slots.
So does PCI-E at least. I assume PCI does too but PCI-E is very fast in comparison. GPUs get 16 lanes of PCI-E, the top slot. Sound cards and similar are fine with 1 lane. NVME SSDs get 4 lanes PCI-E.
So, when you see PCIE16, it means 16 lanes. Your x1 and x2 means 1 and 2 lanes. The slots will be different sizes.

As an aside. In the pic you see three slots with PCIE16. Those usually come with limitations. If you would populate all three slots, you might get something like 8x+8x+4x or 8x+4x+4x in reality. Documention and manual will say what the limitations are.
 

LinuxDevice

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May 20, 2017
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There are already a lot of good replies here, but this might be of interest...

PCI is a protocol for peripheral devices. The original PCI is a parallel physical interface, and PCIe is a serial physical interface. The protocol itself won't change between the two, but the serial PCIe is more "modular" and can use different lane counts, and being serial, those lanes can potentially be much faster than parallel lanes (the timing control becomes more difficult as parallel lane counts go up, but serial has no such timing issue). An 8-lane PCIe slot is "sort of" equivalent to an 8-bit parallel interface transfer so far as 8-bits in parallel would equal 8 lanes with 1 bit on each lane. Overall PCIe is just faster due to the ability to clock individual lanes so much faster, and the ability to pick and choose how many lanes get used.

RAM does not go through PCI or PCIe. It has its own bus access. Peripherals on PCI can be slower than PCIe in many cases, but since RAM has its own highway to the CPU and never touches PCI or PCIe, then there is no logic in the question. If you happen to have an SSD which is part of a PCI or PCIe card (never heard of one on PCI), then this would be a valid question.
 

jasonf2

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Oct 11, 2015
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Ok, so to clarify, can I use either PCI-E or PCI for my RAM and it wouldn't negatively impact my PC performance? Or does RAM connect to the motherboard via an entirely different type of connection? I apologize for me sounding stupid, I am very new to this kind of stuff.

Right now I have an ASUS H87M-PLUS motherboard (not in a complete computer) with an 8GB 1600mhz stick of RAM in one of the ports. I guess I'm not entirely sure which port I plugged it into.

With my motherboard, do you know if it is compatible to have the following exansions:
1 x 8GB 1600mhz
2 x 4GB 1600mhz
1 x Radeon RX 550
1 x (Some form of internal Wi-Fi adapter?)

Or would there not be enough room for all of these components? In particular, I think most internal Wi-Fi adapters use "PCIe x 1" or "PCIe x 2" slots and I'm not sure what those are. All I know is that they are very small.
Let me see if I can break this down.
  1. RAM is on a completely different header configuration than PCI and PCI-E. So if you got it to plug in at all you are on the RAM header. On your board you have 4 slots.
  2. Mix and match RAM can cause issues, but not always. You should install it in pairs and all of them need to be the same.
  3. Your board has 1 X16 PCI-E 3.0 which should run the RX 550
  4. Your board has 1 PCI-E 2.0X16 which should run a wifi adapter. It looks like you could do up to a 4x config on this port. Just fyi a PCIe x1 can plug into an x16 (or any other level of PCI-E) without any issue. The only thing may be if it is a PCI-E 3.0 adapter the card will downgrade to 2.0 bandwidth. Not a big deal on a wifi card.
The two legacy PCI interfaces on your system are pretty much useless unless you have some legacy cards laying around. Nothing has been ran on legacy PCI since PCI-E came into play as it was really pretty much absorbed into PCI-E.
 

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