this set of calculators calculates the time required to complete a download or upload given a specific upload or download bandwidth (speed). it will give the answer in years, months, days, hours, minutes,seconds, and milliseconds in 2 different formats. enjoy.
how much bandwidth should I buy?
a hard disk is slow. its average access time is measured in milliseconds. at say, 7ms average access time, assuming 512 byte sector size, 512*1/7e-3=73,142bytes/sec=71K/sec absolute worst case of only 1 write per access. NTFS groups sectors together, so usually you get about 13-18MB/sec and disks don't usually thrash that badly anyway.
with a windows application I wrote, createfile, I currently get 60/(1*60+12)/60*1000=0.01388GB/sec=13.888MB/sec with a pattern write on a 7200Rpm 2TB hard drive. my processor is a 2.8GHz Pentium 4 HT (1 core 2 thread, looks like 2 procs). that comes out to 0.013888*1e9*8*1.13=119,237,600bits/sec or about 119.2Mbps. newer pc's have the same dilemma: hard disks go at a maximum of 18MB/sec.
this is the maximum speed at which downloads can be written to the hard disk on my machine. what that means is, this is the upper limit for bandwidth on my machine - it wouldn't make any sense to buy a higher speed. an SSD on the other hand, might get better results.
Cable Internet is notorious for slow speeds during busy hours. If lots of people are online on one particular group transmitter and using it, it will bog down (actually, they have gotten better about this in my area). I have seen times where it has gotten down to 25 bytes/second on my 22Mbps line.
Downloading an "update" or patch to a program like Roxio Easy Media Creator Suite 10 (a cd burning program) nowadays requires the fastest broadband internet access you can get, because they are typically 800-900MB now. My Paint Shop Pro X2 update was 44MB. Sometimes, they are not just patching one or two programs – they are replacing the whole package. So brace yourself...
Until I can test on a faster machine, I believe "download speed" is only a marketing ploy. On my very slow Pentium 4 HT 2.8GHz machine (1C, 2 thread) with mcafee (which like any antivirus the firewall acts as an internet proxy and may slow the internet down and be the cause) I consistently get the same download rate as my upload rate. I think the reason why is that TCP/IP, on which nearly every protocol (including HTTP, HTTPS, FTP, and FTPS) is built ises a protocol that involes a formof communication that requires a request and an acknowledgement. this gets into latency (time delays) which slow down the connection and other things. this is why you don't generally try to access servers across the other side of the planet - it's the latency that gets you,plus all those hops between routers and switches which add additional delay. round trip, it all adds up to: SPEED! the inverse of a round-trip time delay in milliseconds is basically speed. another way you can measure your equivalent speed in Mbps is multiply the kBytes/sec you get in the download manager of firefox (or your favorite download maneger for *1* download only (don't download more than 1 thing, it will mess up the numbers). multiply that number by 8 and divide by 1e6 using ttcalc or your favorite calculator. that's kBytes/sec×1e3×8/1e6=Mbps. that's assuming they are not using IEC units of course. if they are, that would be kiBytes/sec×1024×8/1e6=Mbps. the 8 is for 8 bits in a byte (they call it an octet in networking parlance), and the 1024=1KiB whereas 1000=1KB. on my computer using comcast standard internet with tv, I get 20Mbps/3Mbps according to speedtest.net however, I think because of the round-trip request/ack I only get the upload speed which is 3Mbps for my download speed. so they can advertise 20Mbps all they want it's not doing me any good. If you are getting results to the contrary on your fast computer, PLEASE tell me. I want to know. use the Contact Me page.