What is the maximum memory for this computer?

Pull up a RUN box. Windows key plus R. Then type in cmd and hit enter. Next, using the command prompt that has appeared, type in wmic memphysical get MaxCapacity, MemoryDevices

Hit enter.

Copy the number you see and devide that by 1048576
You can actually do that in the address bar of your browser.
That will give you the maximum gigabytes your computer will run.

https://www.maketecheasier.com/how-to-find-out-maximum-ram-capacity-of-computer/

Try 4 all memory at:

http://www.4allmemory.com

The link below is a direct link to your model. It state's that there are 2 slots in your computer and that it will hold a maximum of 2 Gigabytes (1 Gigabyte in each slot). The Memory Type is: DDR2 PC2-3200 or DDR2 PC2-4200

http://www.4allmemory.com/memory/dell-dimension-3100/

Do you have the right memory for your Dell?
Memory Upgrade for Dell Dimension 1100 Computer, the Dell Dimension 1100 Computer takes the PC2700/3200 DDR SDRAM DIMMs. Supports Dual Channel DDR. Memory Type, and comes installed with 128 MB (removable) of Memory. You can upgrade your Dell Dimension 1100 Computer to up to a maximum of 2.0 GB Memory, the system has 2 sockets to install Memory, already with 128 MB (removable) standard Memory installed. For best Computer performance use the maximum amount of allowed Memory per slot for your Computer.
Choose the following Memory Upgrade for Dell Dimension 1100 Computer.

I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_8b8c2cd6ce148309

Maximum allowed 4 GB* (4 x 1 GB) requires the replacement of the installed 256 MB DIMMs

*Actual available memory may be less Maximum allowed 4 GB* (4 x 1 GB) requires the replacement of the installed 256 MB DIMMs

*Actual available memory may be lessThere will be 4 slots for the memory, you can use 4 memory cards of 1 GB each meaning thereby u can use 4 GB maximum.

You could have tried GOOGLE.
Your computer has 64mb ram built in and can take a maximum of 320mb. You have 1 slot to add memory too
You can add 256MB, 144-pin SODIMM, SDRAM, PC133

FixYa is a product support website, and as such we do not delve into manufacturing. No we cannot supply ram memory.

I can supply you with the solution to your questions, however.

This is HP Support, and the main page for the Pavilion 513n Desktop PC,

http://h10025.www1.hp.com/ewfrf/wc/product?product=90384&lc=en&cc=us&dlc=en&submit.y=5&submit.x=6&lang=en&cc=us

If you click on > Product information > Product specifications > HP Pavilion 513n Desktop PC Product Specifications,
you can view,

A) What type of ram memory the computer uses,
B) How much is the Maximum Total Amount for the computer,
C) How much is the Maximum Amount for EACH ram slot,
D) How many ram slots

Look under the Memory heading.
A) What type of ram memory
Type - DDR
It's DDR Sdram

Speed - PC1600/PC2100
Tells you either PC1600 can be used, or PC2100.

PC1600 is DDR Sdram that operates at 200MHz.
PC2100 is DDR Sdram that operates at 266MHz.

{To expound:
Ram memory operates at a Frequency Rate. Slang for frequency rate is 'Speed'.
Mega = approximately 1 Million
Hertz stands for Cycles per Second
Example: PC2100 is DDR Sdram that operates at 266 Million Cycles per Second }

B) What is the Maximum Total Amount for the computer. (Motherboard)
According to HP it is 1GB.

{Maximum - 1GB (2 X 512) HP recommended maximum}

I believe this to be wrong. The Total Maximum Amount is 2GB.
1GB per ram slot.

I base this upon using the memory configurator's of several websites, that sell ram memory for the Pavilion 513n desktop computer, and looking at what the motherboard chipset for the Pavilion 513n will support.

The motherboard chipset is the Intel 845GL.
This chart found on Wikipedia, states what the Intel 845GL chipset will support,

http://en.wikipedia.org/wiki/List_of_Intel_chipsets#Pentium_4_Chipsets

As you can see reading across from the 845GL subheading, and looking under > Max.memory, 2GB is listed.

Sources for online memory configurators,
1) Crucial.com
2) Tigerdirect.com
3) Newegg.com
4) Memory4less.net

In this case,
C) Maximum Amount for EACH ram slot is 1GB.

D) There are Two ram slots. {Proper speak for ram Slot is ram Bank}

Kingston is a good brand for economical ram memory.
So is Ultra.

An easy way to find out what type of ram memory you need, and how much is the Maximum Total Amount, as well as the Maximum Amount for Each ram slot, is to use an automatic scanner from a website that sells ram memory.

The above four websites listed, are but a small handful of the total websites online that offer an automatic scan.
Let's use Crucial.com for an example.

On the main page,

http://www.crucial.com/

,you will see - Scan My System, in blue.
Simply click on it to run an automatic scan of your computers hardware.
Doesn't look at your personal effects, just the hardware of your computer.

After the scan is done, you will be presented with the ram memory info you need.
Several options of ram memory are presented for you to choose from.

Go to www.crucial.com and click on the scan my system button to see what configuration of Memory Modules are installed on your laptop.

Here are some other details:

Each memory slot can hold DDR2 PC2-5300 with a maximum of 1GB per slot.
Chipset: Intel 960GML
Drive Form Factor: 2.5"
Drive Interface: SATA
Maximum Memory: 2048MB
Slots: 2 (2 banks of 1)
Standard Memory: 512MB removable
USB Support: 2.x Compliant

Q: What memory goes into my computer, and will a faster speed be backward-compatible?
A: DDR2 memory with support for DDR2 PC2-5300 speeds.

Q: How much memory can my computer handle?
A: 2048MB.

Adding the maximum amount of memory will improve performance and help extend the useful life of your system as you run increasingly demanding software applications in the future.

Q: Do I have to install matching pairs?
A: No.

No, you can install modules one at a time, and you can mix different densities of modules in your computer. But if your computer supports dual-channel memory configurations, you should install in identical pairs (preferably in kits) for optimal performance.

Q: Does my computer support dual-channel memory?
A: Yes.

4G DDR SDRAM

Look closely at the BOLD print

Memory Upgrade for eMachines eMachines T5082 Computer, the eMachines eMachines T5082 Computer takes the PC2-4200 DDR2 SDRAM DIMMs. Supports Dual Channel DDR2. Memory Type, and comes installed with 512 MB (removable) of Memory. You can upgrade your eMachines eMachines T5082 Computer to up to a maximum of 2.0 GB Memory, the system has 2 sockets to install Memory, already with 512 MB (removable) standard Memory installed. For best Computer performance use the maximum amount of allowed Memory per slot for your Computer.
Choose the following Memory Upgrade for eMachines eMachines T5082 Computer.

No, The reason why your computer says it has lower memory is because either

A- your bios can only recognize up to 320mb. --possible fix via upgrading/flashing your bios --check manufacturer's website.
B- your on board video card shares memory with the system.