Some questions about buying the latest Mac Minis

in Genius Bar edited June 2015

Hi, everyone. I could use some advice. 


Here's my situation:


I have a 24" IMac that I bought in 2007. It's running Yosemite and has 4GB of RAM.


This past week, I had kernel panics for five straight days. I'd never had them before and I hadn't made any major changes to my Mac. At the time, I didn't know that kernel panics could be software-related. I thought the iMac was finally dying so I panicked and I decided to buy a new computer. I'm currently unemployed so I wanted to spend as little as possible, but also get something that would be a reasonable upgrade.


So I ordered a refurbished Mac Mini from the Apple online store. It's the model with a 2.8hz i5 processor, a 1TB Fusion drive and 8GB of RAM. It cost $850 + $80 tax. I also had to buy an external monitor, and some cables, which I did from Amazon for about $300 more.


The computer and monitor have arrived, but I haven't opened the boxes because I'm thinking that I might send them back. One reason is that I haven't had a kernel panic for a few days, so I'm not feeling as desperate -- though I want to wait a little longer to see if the kernel panics happen again.


The other reason -- and the main reason -- I might send the equipment back is that I have a nagging feeling that buying a computer with only 8GB of RAM, instead of 16GB, is a mistake. I just think a computer with 16GB will meet my future needs better than one with only 8GB -- but I could be wrong, because  I might never need more than 8GB.


In terms of my current memory usage: I usually have a bunch of apps running. According to Activity Monitor, right now I am using 3.42GB of memory including 1.12GB of Swap space (not sure if that means the hard drive is being used as virtual memory). So maybe only 8GB will work for me, but I'm not sure. I also think the graphics card on the Mini may use some RAM. 


I decided to see how much it would cost to buy a Mac Mini with a 2.6 Ghz processor, 16GB of RAM and 1 TB Fusion drive -- so the processor would be slower than the Mini I bought, but the computer would have more RAM. Because the computer is not refurbished, it would cost $1099 plus tax, which I'm  guessing would be another $100, so $1200 total. So it would be  about $280 more than the Mini I already bought. I'm not sure I can afford the extra $280, but, again, I worry that a computer with only 8GB of RAM is a bad investment.


Although, I suppose, if I keep the Mac I ordered, that I could just run less programs at a time to make sure the 8GB is enough.


So my questions are: What would you do in my situation? What are the performance differences between the 2.8Ghz with 8GB of RAM vs the 2.6Ghz model with 16GB RAM? Also, if the graphics card uses regular RAM, does that mean I would actually have less than 8GB?




  • Reply 1 of 3
    hmmhmm Posts: 3,405member

    The graphics don't take up that much memory. 8 vs 16 depends on how much memory your applications consume. If you don't have a high level of swapping at any given time, it won't affect much. There are a lot of things that can benefit from more than 8GB, but this has been true for a long time. The number that benefit from more than 16 is far less. It's not a consistent speedup. Memory reduces the need for swaps. Memory is many times faster than even an ssd, and roughly 100x faster than a 7200rpm hard drive, and a swap isn't a simple operation anyway (has to move something to disk and move the required address to a location in physical memory). If this happens many times over a short period of time, you perceive it as lag.


    Did you change anything in terms of hardware with your imac? Did you check the dump logs? It's not always obvious. Sometimes people upgrade memory without testing the new ram and experience kernel panics due to bit flips on the newly purchased ram, specifically relating to some critical address.

  • Reply 2 of 3
    mirskymirsky Posts: 30member

    Keylogger, thanks for much responding. I ended up deciding that 8GB of RAM is enough my purposes, at least for the near future. 


    I didn't change anything on the iMac. I didn't know anything about dump logs, but I've looked them up online. Thanks for mentioning them.


    Online I was able to find Apple Hardware Test for my iMac. I ran it and the hardware tested fine.


    So I'm writing on the new Mac Mini and I've decided to use the iMac as a second monitor using Screen Recyler and for Skype (the iMac's Isight camera is better than the one I bought for the Mini). I erased the iMac's hard drive and I installed a fresh install of Yosemite, so hopefully I won't get any more kernel panics. 


    Thanks again!

  • Reply 3 of 3
    hmmhmm Posts: 3,405member

    They don't always help. They indicate the contents of a running process at the time something unrecoverable occurred. Sometimes looking through them reveals things such as the mention of a specific driver that may have caused the exception. Many people are fine with 8GB. Apple's markup is a bit steep on the 8 -> 16 option.

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